diff --git a/app/Enums/TimeEntryRoundingType.php b/app/Enums/TimeEntryRoundingType.php
new file mode 100644
index 00000000..7300f8ac
--- /dev/null
+++ b/app/Enums/TimeEntryRoundingType.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Enums;
+
+use Datomatic\LaravelEnumHelper\LaravelEnumHelper;
+
+enum TimeEntryRoundingType: string
+{
+    use LaravelEnumHelper;
+
+    case Up = 'up';
+    case Down = 'down';
+    case Nearest = 'nearest';
+}
diff --git a/app/Http/Controllers/Api/V1/Public/ReportController.php b/app/Http/Controllers/Api/V1/Public/ReportController.php
index 739fa008..1aec632f 100644
--- a/app/Http/Controllers/Api/V1/Public/ReportController.php
+++ b/app/Http/Controllers/Api/V1/Public/ReportController.php
@@ -73,7 +73,9 @@ class ReportController extends Controller
             false,
             $report->properties->start,
             $report->properties->end,
-            true
+            true,
+            $report->properties->roundingType,
+            $report->properties->roundingMinutes,
         );
         $historyData = $timeEntryAggregationService->getAggregatedTimeEntriesWithDescriptions(
             $timeEntriesQuery->clone(),
@@ -84,7 +86,9 @@ class ReportController extends Controller
             true,
             $report->properties->start,
             $report->properties->end,
-            true
+            true,
+            $report->properties->roundingType,
+            $report->properties->roundingMinutes,
         );
 
         return new DetailedWithDataReportResource($report, $data, $historyData);
diff --git a/app/Http/Controllers/Api/V1/TimeEntryController.php b/app/Http/Controllers/Api/V1/TimeEntryController.php
index 1e69d928..a2bb23ac 100644
--- a/app/Http/Controllers/Api/V1/TimeEntryController.php
+++ b/app/Http/Controllers/Api/V1/TimeEntryController.php
@@ -33,6 +33,7 @@ use App\Service\ReportExport\TimeEntriesDetailedExport;
 use App\Service\ReportExport\TimeEntriesReportExport;
 use App\Service\TimeEntryAggregationService;
 use App\Service\TimeEntryFilter;
+use App\Service\TimeEntryService;
 use App\Service\TimezoneService;
 use Gotenberg\Exceptions\GotenbergApiErrored;
 use Gotenberg\Exceptions\NoOutputFileInResponse;
@@ -47,6 +48,7 @@ use Illuminate\Http\Resources\Json\JsonResource;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Facades\Auth;
 use Illuminate\Support\Facades\Blade;
+use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Storage;
 use Maatwebsite\Excel\Facades\Excel;
@@ -140,8 +142,15 @@ class TimeEntryController extends Controller
      */
     private function getTimeEntriesQuery(Organization $organization, TimeEntryIndexRequest|TimeEntryIndexExportRequest $request, ?Member $member): Builder
     {
+        $select = TimeEntry::SELECT_COLUMNS;
+        if ($request->getRoundingType() !== null && $request->getRoundingMinutes() !== null) {
+            $select = array_diff($select, ['start', 'end']);
+            $select[] = DB::raw(app(TimeEntryService::class)->getStartSelectRawForRounding($request->getRoundingType(), $request->getRoundingMinutes()).' as start');
+            $select[] = DB::raw(app(TimeEntryService::class)->getEndSelectRawForRounding($request->getRoundingType(), $request->getRoundingMinutes()).' as end');
+        }
         $timeEntriesQuery = TimeEntry::query()
             ->whereBelongsTo($organization, 'organization')
+            ->select($select)
             ->orderBy('start', 'desc');
 
         $filter = new TimeEntryFilter($timeEntriesQuery);
@@ -183,6 +192,8 @@ class TimeEntryController extends Controller
         $user = $this->user();
         $timezone = $user->timezone;
         $showBillableRate = $this->member($organization)->role !== Role::Employee->value || $organization->employees_can_see_billable_rates;
+        $roundingType = $request->getRoundingType();
+        $roundingMinutes = $request->getRoundingMinutes();
 
         $timeEntriesQuery = $this->getTimeEntriesQuery($organization, $request, $member);
         $timeEntriesQuery->with([
@@ -207,8 +218,9 @@ class TimeEntryController extends Controller
             if ($viewFile === false) {
                 throw new \LogicException('View file not found');
             }
+            $timeEntriesAggregateQuery = $this->getTimeEntriesAggregateQuery($organization, $request, $member);
             $aggregatedData = $timeEntryAggregationService->getAggregatedTimeEntries(
-                $timeEntriesQuery->clone()->reorder()->withOnly([]),
+                $timeEntriesAggregateQuery,
                 null,
                 null,
                 $user->timezone,
@@ -216,7 +228,9 @@ class TimeEntryController extends Controller
                 false,
                 null,
                 null,
-                $showBillableRate
+                $showBillableRate,
+                $roundingType,
+                $roundingMinutes,
             );
             $html = Blade::render($viewFile, [
                 'timeEntries' => $timeEntriesQuery->get(),
@@ -324,6 +338,8 @@ class TimeEntryController extends Controller
         $group1Type = $request->getGroup();
         $group2Type = $request->getSubGroup();
         $timeEntriesAggregateQuery = $this->getTimeEntriesAggregateQuery($organization, $request, $member);
+        $roundingType = $request->getRoundingType();
+        $roundingMinutes = $request->getRoundingMinutes();
 
         $aggregatedData = $timeEntryAggregationService->getAggregatedTimeEntries(
             $timeEntriesAggregateQuery,
@@ -334,7 +350,9 @@ class TimeEntryController extends Controller
             $request->getFillGapsInTimeGroups(),
             $request->getStart(),
             $request->getEnd(),
-            $showBillableRate
+            $showBillableRate,
+            $roundingType,
+            $roundingMinutes
         );
 
         return [
@@ -373,6 +391,8 @@ class TimeEntryController extends Controller
         $group = $request->getGroup();
         $subGroup = $request->getSubGroup();
         $timeEntriesAggregateQuery = $this->getTimeEntriesAggregateQuery($organization, $request, $member);
+        $roundingType = $request->getRoundingType();
+        $roundingMinutes = $request->getRoundingMinutes();
 
         $aggregatedData = $timeEntryAggregationService->getAggregatedTimeEntriesWithDescriptions(
             $timeEntriesAggregateQuery->clone(),
@@ -383,7 +403,9 @@ class TimeEntryController extends Controller
             false,
             $request->getStart(),
             $request->getEnd(),
-            $showBillableRate
+            $showBillableRate,
+            $roundingType,
+            $roundingMinutes
         );
         $dataHistoryChart = $timeEntryAggregationService->getAggregatedTimeEntries(
             $timeEntriesAggregateQuery->clone(),
@@ -394,7 +416,9 @@ class TimeEntryController extends Controller
             true,
             $request->getStart(),
             $request->getEnd(),
-            $showBillableRate
+            $showBillableRate,
+            $roundingType,
+            $roundingMinutes
         );
         $currency = $organization->currency;
         $timezone = app(TimezoneService::class)->getTimezoneFromUser($this->user());
@@ -477,7 +501,7 @@ class TimeEntryController extends Controller
     /**
      * @return Builder<TimeEntry>
      */
-    private function getTimeEntriesAggregateQuery(Organization $organization, TimeEntryAggregateRequest|TimeEntryAggregateExportRequest $request, ?Member $member): Builder
+    private function getTimeEntriesAggregateQuery(Organization $organization, TimeEntryAggregateRequest|TimeEntryAggregateExportRequest|TimeEntryIndexExportRequest $request, ?Member $member): Builder
     {
         $timeEntriesQuery = TimeEntry::query()
             ->whereBelongsTo($organization, 'organization');
diff --git a/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateExportRequest.php b/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateExportRequest.php
index 7c33242b..35f84519 100644
--- a/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateExportRequest.php
+++ b/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateExportRequest.php
@@ -7,6 +7,7 @@ namespace App\Http\Requests\V1\TimeEntry;
 use App\Enums\ExportFormat;
 use App\Enums\TimeEntryAggregationType;
 use App\Enums\TimeEntryAggregationTypeInterval;
+use App\Enums\TimeEntryRoundingType;
 use App\Http\Requests\V1\BaseFormRequest;
 use App\Models\Client;
 use App\Models\Member;
@@ -164,6 +165,18 @@ class TimeEntryAggregateExportRequest extends BaseFormRequest
                 'string',
                 'in:true,false',
             ],
+            // Rounding type defined where the end of each time entry should be rounded to. For example: nearest rounds the end to the nearest x minutes group. Rounding per time entry is activated if `rounding_type` and `rounding_minutes` is not null.
+            'rounding_type' => [
+                'nullable',
+                'string',
+                Rule::enum(TimeEntryRoundingType::class),
+            ],
+            // Defines the length of the interval that the time entry rounding rounds to.
+            'rounding_minutes' => [
+                'nullable',
+                'numeric',
+                'integer',
+            ],
         ];
     }
 
@@ -211,4 +224,22 @@ class TimeEntryAggregateExportRequest extends BaseFormRequest
     {
         return ExportFormat::from($this->validated('format'));
     }
+
+    public function getRoundingType(): ?TimeEntryRoundingType
+    {
+        if (! $this->has('rounding_type') || $this->validated('rounding_type') === null) {
+            return null;
+        }
+
+        return TimeEntryRoundingType::from($this->validated('rounding_type'));
+    }
+
+    public function getRoundingMinutes(): ?int
+    {
+        if (! $this->has('rounding_minutes') || $this->validated('rounding_minutes') === null) {
+            return null;
+        }
+
+        return (int) $this->validated('rounding_minutes');
+    }
 }
diff --git a/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateRequest.php b/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateRequest.php
index 45db56cb..39c9270e 100644
--- a/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateRequest.php
+++ b/app/Http/Requests/V1/TimeEntry/TimeEntryAggregateRequest.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Http\Requests\V1\TimeEntry;
 
 use App\Enums\TimeEntryAggregationType;
+use App\Enums\TimeEntryRoundingType;
 use App\Http\Requests\V1\BaseFormRequest;
 use App\Models\Client;
 use App\Models\Member;
@@ -146,6 +147,18 @@ class TimeEntryAggregateRequest extends BaseFormRequest
                 'string',
                 'in:true,false',
             ],
+            // Rounding type defined where the end of each time entry should be rounded to. For example: nearest rounds the end to the nearest x minutes group. Rounding per time entry is activated if `rounding_type` and `rounding_minutes` is not null.
+            'rounding_type' => [
+                'nullable',
+                'string',
+                Rule::enum(TimeEntryRoundingType::class),
+            ],
+            // Defines the length of the interval that the time entry rounding rounds to.
+            'rounding_minutes' => [
+                'nullable',
+                'numeric',
+                'integer',
+            ],
         ];
     }
 
@@ -173,4 +186,22 @@ class TimeEntryAggregateRequest extends BaseFormRequest
     {
         return $this->input('end') !== null ? Carbon::createFromFormat('Y-m-d\TH:i:s\Z', $this->input('end'), 'UTC') : null;
     }
+
+    public function getRoundingType(): ?TimeEntryRoundingType
+    {
+        if (! $this->has('rounding_type') || $this->validated('rounding_type') === null) {
+            return null;
+        }
+
+        return TimeEntryRoundingType::from($this->validated('rounding_type'));
+    }
+
+    public function getRoundingMinutes(): ?int
+    {
+        if (! $this->has('rounding_minutes') || $this->validated('rounding_minutes') === null) {
+            return null;
+        }
+
+        return (int) $this->validated('rounding_minutes');
+    }
 }
diff --git a/app/Http/Requests/V1/TimeEntry/TimeEntryIndexExportRequest.php b/app/Http/Requests/V1/TimeEntry/TimeEntryIndexExportRequest.php
index 84c21562..6c3180b2 100644
--- a/app/Http/Requests/V1/TimeEntry/TimeEntryIndexExportRequest.php
+++ b/app/Http/Requests/V1/TimeEntry/TimeEntryIndexExportRequest.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Http\Requests\V1\TimeEntry;
 
 use App\Enums\ExportFormat;
+use App\Enums\TimeEntryRoundingType;
 use App\Models\Member;
 use App\Models\Organization;
 use App\Models\Project;
@@ -133,6 +134,18 @@ class TimeEntryIndexExportRequest extends TimeEntryIndexRequest
                 'string',
                 'in:true,false',
             ],
+            // Rounding type defined where the end of each time entry should be rounded to. For example: nearest rounds the end to the nearest x minutes group. Rounding per time entry is activated if `rounding_type` and `rounding_minutes` is not null.
+            'rounding_type' => [
+                'nullable',
+                'string',
+                Rule::enum(TimeEntryRoundingType::class),
+            ],
+            // Defines the length of the interval that the time entry rounding rounds to.
+            'rounding_minutes' => [
+                'nullable',
+                'numeric',
+                'integer',
+            ],
         ];
     }
 
@@ -170,4 +183,22 @@ class TimeEntryIndexExportRequest extends TimeEntryIndexRequest
     {
         return ExportFormat::from($this->validated('format'));
     }
+
+    public function getRoundingType(): ?TimeEntryRoundingType
+    {
+        if (! $this->has('rounding_type') || $this->validated('rounding_type') === null) {
+            return null;
+        }
+
+        return TimeEntryRoundingType::from($this->validated('rounding_type'));
+    }
+
+    public function getRoundingMinutes(): ?int
+    {
+        if (! $this->has('rounding_minutes') || $this->validated('rounding_minutes') === null) {
+            return null;
+        }
+
+        return (int) $this->validated('rounding_minutes');
+    }
 }
diff --git a/app/Http/Requests/V1/TimeEntry/TimeEntryIndexRequest.php b/app/Http/Requests/V1/TimeEntry/TimeEntryIndexRequest.php
index 19203cbb..c6463d79 100644
--- a/app/Http/Requests/V1/TimeEntry/TimeEntryIndexRequest.php
+++ b/app/Http/Requests/V1/TimeEntry/TimeEntryIndexRequest.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Http\Requests\V1\TimeEntry;
 
+use App\Enums\TimeEntryRoundingType;
 use App\Http\Requests\V1\BaseFormRequest;
 use App\Models\Client;
 use App\Models\Member;
@@ -11,8 +12,11 @@ use App\Models\Organization;
 use App\Models\Project;
 use App\Models\Tag;
 use App\Models\Task;
+use Illuminate\Contracts\Validation\Rule as RuleContract;
 use Illuminate\Contracts\Validation\ValidationRule;
 use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
 use Korridor\LaravelModelValidationRules\Rules\ExistsEloquent;
 
 /**
@@ -23,7 +27,7 @@ class TimeEntryIndexRequest extends BaseFormRequest
     /**
      * Get the validation rules that apply to the request.
      *
-     * @return array<string, array<string|ValidationRule>>
+     * @return array<string, array<string|ValidationRule|RuleContract>>
      */
     public function rules(): array
     {
@@ -136,6 +140,18 @@ class TimeEntryIndexRequest extends BaseFormRequest
                 'string',
                 'in:true,false',
             ],
+            // Rounding type defined where the end of each time entry should be rounded to. For example: nearest rounds the end to the nearest x minutes group. Rounding per time entry is activated if `rounding_type` and `rounding_minutes` is not null.
+            'rounding_type' => [
+                'nullable',
+                'string',
+                Rule::enum(TimeEntryRoundingType::class),
+            ],
+            // Defines the length of the interval that the time entry rounding rounds to.
+            'rounding_minutes' => [
+                'nullable',
+                'numeric',
+                'integer',
+            ],
         ];
     }
 
@@ -153,4 +169,22 @@ class TimeEntryIndexRequest extends BaseFormRequest
     {
         return $this->has('offset') ? (int) $this->validated('offset', 0) : 0;
     }
+
+    public function getRoundingType(): ?TimeEntryRoundingType
+    {
+        if (! $this->has('rounding_type') || $this->validated('rounding_type') === null) {
+            return null;
+        }
+
+        return TimeEntryRoundingType::from($this->validated('rounding_type'));
+    }
+
+    public function getRoundingMinutes(): ?int
+    {
+        if (! $this->has('rounding_minutes') || $this->validated('rounding_minutes') === null) {
+            return null;
+        }
+
+        return (int) $this->validated('rounding_minutes');
+    }
 }
diff --git a/app/Models/TimeEntry.php b/app/Models/TimeEntry.php
index de4576a9..6143111e 100644
--- a/app/Models/TimeEntry.php
+++ b/app/Models/TimeEntry.php
@@ -77,6 +77,26 @@ class TimeEntry extends Model implements AuditableContract
         'still_active_email_sent_at' => 'datetime',
     ];
 
+    public const array SELECT_COLUMNS = [
+        'id',
+        'description',
+        'start',
+        'end',
+        'billable_rate',
+        'billable',
+        'user_id',
+        'organization_id',
+        'project_id',
+        'task_id',
+        'tags',
+        'created_at',
+        'updated_at',
+        'member_id',
+        'client_id',
+        'is_imported',
+        'still_active_email_sent_at',
+    ];
+
     /**
      * The attributes that are computed. (f.e. for performance reasons)
      * These attributes can be regenerated at any time.
diff --git a/app/Service/Dto/ReportPropertiesDto.php b/app/Service/Dto/ReportPropertiesDto.php
index 892f4eb1..ac056d0f 100644
--- a/app/Service/Dto/ReportPropertiesDto.php
+++ b/app/Service/Dto/ReportPropertiesDto.php
@@ -6,6 +6,7 @@ namespace App\Service\Dto;
 
 use App\Enums\TimeEntryAggregationType;
 use App\Enums\TimeEntryAggregationTypeInterval;
+use App\Enums\TimeEntryRoundingType;
 use App\Enums\Weekday;
 use Illuminate\Contracts\Database\Eloquent\Castable;
 use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
@@ -59,6 +60,10 @@ class ReportPropertiesDto implements Castable
      */
     public ?Collection $taskIds = null;
 
+    public ?TimeEntryRoundingType $roundingType = null;
+
+    public ?int $roundingMinutes = null;
+
     /**
      * Get the caster class to use when casting from / to this cast target.
      *
@@ -115,6 +120,10 @@ class ReportPropertiesDto implements Castable
                 $dto->historyGroup = TimeEntryAggregationTypeInterval::from($data->historyGroup);
                 $dto->weekStart = Weekday::from($data->weekStart);
                 $dto->timezone = $data->timezone;
+                // Note: roundingType was added later so it is possible that the value is missing in persisted reports in the DB
+                $dto->roundingType = isset($data->roundingType) ? TimeEntryRoundingType::from($data->roundingType) : null;
+                // Note: roundingMinutes was added later so it is possible that the value is missing in persisted reports in the DB
+                $dto->roundingMinutes = isset($data->roundingMinutes) ? (int) $data->roundingMinutes : null;
 
                 return $dto;
             }
@@ -140,6 +149,8 @@ class ReportPropertiesDto implements Castable
                     'historyGroup' => $value->historyGroup->value,
                     'weekStart' => $value->weekStart->value,
                     'timezone' => $value->timezone,
+                    'roundingType' => $value->roundingType?->value,
+                    'roundingMinutes' => $value->roundingMinutes,
                 ];
 
                 $jsonString = json_encode($data);
diff --git a/app/Service/TimeEntryAggregationService.php b/app/Service/TimeEntryAggregationService.php
index a662011a..a59becbd 100644
--- a/app/Service/TimeEntryAggregationService.php
+++ b/app/Service/TimeEntryAggregationService.php
@@ -6,6 +6,7 @@ namespace App\Service;
 
 use App\Enums\TimeEntryAggregationType;
 use App\Enums\TimeEntryAggregationTypeInterval;
+use App\Enums\TimeEntryRoundingType;
 use App\Enums\Weekday;
 use App\Models\Client;
 use App\Models\Project;
@@ -41,7 +42,7 @@ class TimeEntryAggregationService
      *       cost: int|null
      * }
      */
-    public function getAggregatedTimeEntries(Builder $timeEntriesQuery, ?TimeEntryAggregationType $group1Type, ?TimeEntryAggregationType $group2Type, string $timezone, Weekday $startOfWeek, bool $fillGapsInTimeGroups, ?Carbon $start, ?Carbon $end, bool $showBillableRate): array
+    public function getAggregatedTimeEntries(Builder $timeEntriesQuery, ?TimeEntryAggregationType $group1Type, ?TimeEntryAggregationType $group2Type, string $timezone, Weekday $startOfWeek, bool $fillGapsInTimeGroups, ?Carbon $start, ?Carbon $end, bool $showBillableRate, ?TimeEntryRoundingType $roundingType, ?int $roundingMinutes): array
     {
         $fillGapsInTimeGroupsIsPossible = $fillGapsInTimeGroups && $start !== null && $end !== null;
         $group1Select = null;
@@ -56,15 +57,14 @@ class TimeEntryAggregationService
             }
         }
 
+        $startRawSelect = app(TimeEntryService::class)->getStartSelectRawForRounding($roundingType, $roundingMinutes);
+        $endRawSelect = app(TimeEntryService::class)->getEndSelectRawForRounding($roundingType, $roundingMinutes);
+
         $timeEntriesQuery->selectRaw(
             ($group1Select !== null ? $group1Select.' as group_1,' : '').
             ($group2Select !== null ? $group2Select.' as group_2,' : '').
-            ' round(sum(extract(epoch from (coalesce("end", now()) - start)))) as aggregate,'.
-            ' round(
-                  sum(
-                      extract(epoch from (coalesce("end", now()) - start)) * (coalesce(billable_rate, 0)::float/60/60)
-                  )
-              ) as cost'
+            ' round(sum(extract(epoch from ('.$endRawSelect.' - '.$startRawSelect.')))) as aggregate,'.
+            ' round(sum(extract(epoch from ('.$endRawSelect.' - '.$startRawSelect.')) * (coalesce(billable_rate, 0)::float/60/60))) as cost'
         );
         if ($groupBy !== null) {
             $timeEntriesQuery->groupBy($groupBy);
@@ -164,9 +164,9 @@ class TimeEntryAggregationService
      *       cost: int|null
      * }
      */
-    public function getAggregatedTimeEntriesWithDescriptions(Builder $timeEntriesQuery, ?TimeEntryAggregationType $group1Type, ?TimeEntryAggregationType $group2Type, string $timezone, Weekday $startOfWeek, bool $fillGapsInTimeGroups, ?Carbon $start, ?Carbon $end, bool $showBillableRate): array
+    public function getAggregatedTimeEntriesWithDescriptions(Builder $timeEntriesQuery, ?TimeEntryAggregationType $group1Type, ?TimeEntryAggregationType $group2Type, string $timezone, Weekday $startOfWeek, bool $fillGapsInTimeGroups, ?Carbon $start, ?Carbon $end, bool $showBillableRate, ?TimeEntryRoundingType $roundingType, ?int $roundingMinutes): array
     {
-        $aggregatedTimeEntries = $this->getAggregatedTimeEntries($timeEntriesQuery, $group1Type, $group2Type, $timezone, $startOfWeek, $fillGapsInTimeGroups, $start, $end, $showBillableRate);
+        $aggregatedTimeEntries = $this->getAggregatedTimeEntries($timeEntriesQuery, $group1Type, $group2Type, $timezone, $startOfWeek, $fillGapsInTimeGroups, $start, $end, $showBillableRate, $roundingType, $roundingMinutes);
 
         $keysGroup1 = [];
         $keysGroup2 = [];
diff --git a/app/Service/TimeEntryService.php b/app/Service/TimeEntryService.php
new file mode 100644
index 00000000..6cd97aa5
--- /dev/null
+++ b/app/Service/TimeEntryService.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Enums\TimeEntryRoundingType;
+use Illuminate\Support\Carbon;
+use LogicException;
+
+class TimeEntryService
+{
+    public function getStartSelectRawForRounding(?TimeEntryRoundingType $roundingType, ?int $roundingMinutes): string
+    {
+        if ($roundingType === null || $roundingMinutes === null) {
+            return 'start';
+        }
+        if ($roundingMinutes < 1) {
+            throw new LogicException('Rounding minutes must be greater than 0');
+        }
+
+        return 'date_bin(\'1 minutes\', start, TIMESTAMP \'1970-01-01\')';
+    }
+
+    public function getEndSelectRawForRounding(?TimeEntryRoundingType $roundingType, ?int $roundingMinutes): string
+    {
+        if ($roundingType === null || $roundingMinutes === null) {
+            return 'coalesce("end", \''.Carbon::now()->toDateTimeString().'\')';
+        }
+        if ($roundingMinutes < 1) {
+            throw new LogicException('Rounding minutes must be greater than 0');
+        }
+        $end = 'coalesce("end", \''.Carbon::now()->toDateTimeString().'\')';
+        if ($roundingType === TimeEntryRoundingType::Down) {
+            return 'date_bin(\''.$roundingMinutes.' minutes\', '.$end.', '.$this->getStartSelectRawForRounding($roundingType, $roundingMinutes).')';
+        } elseif ($roundingType === TimeEntryRoundingType::Up) {
+            return 'date_bin(\''.$roundingMinutes.' minutes\', '.$end.' + interval \''.$roundingMinutes.' minutes\', '.$this->getStartSelectRawForRounding($roundingType, $roundingMinutes).')';
+        } elseif ($roundingType === TimeEntryRoundingType::Nearest) {
+            return 'date_bin(\''.$roundingMinutes.' minutes\', '.$end.' + interval \''.($roundingMinutes / 2).' minutes\', '.$this->getStartSelectRawForRounding($roundingType, $roundingMinutes).')';
+        }
+    }
+}
diff --git a/database/factories/TimeEntryFactory.php b/database/factories/TimeEntryFactory.php
index 72e10bf1..863df443 100644
--- a/database/factories/TimeEntryFactory.php
+++ b/database/factories/TimeEntryFactory.php
@@ -153,6 +153,16 @@ class TimeEntryFactory extends Factory
         });
     }
 
+    public function endWithDuration(Carbon $end, int $durationInSeconds): self
+    {
+        return $this->state(function (array $attributes) use ($end, $durationInSeconds): array {
+            return [
+                'start' => $end->copy()->utc()->subSeconds($durationInSeconds),
+                'end' => $end->copy()->utc(),
+            ];
+        });
+    }
+
     public function start(Carbon $start): self
     {
         return $this->state(function (array $attributes) use ($start): array {
diff --git a/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php b/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
index 69742587..c1ba8a95 100644
--- a/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
+++ b/tests/Unit/Endpoint/Api/V1/TimeEntryEndpointTest.php
@@ -8,6 +8,7 @@ use App\Enums\ExportFormat;
 use App\Enums\Role;
 use App\Enums\TimeEntryAggregationType;
 use App\Enums\TimeEntryAggregationTypeInterval;
+use App\Enums\TimeEntryRoundingType;
 use App\Exceptions\Api\TimeEntryCanNotBeRestartedApiException;
 use App\Http\Controllers\Api\V1\TimeEntryController;
 use App\Jobs\RecalculateSpentTimeForProject;
@@ -389,6 +390,141 @@ class TimeEntryEndpointTest extends ApiEndpointTestAbstract
         );
     }
 
+    public function test_index_endpoint_can_round_up(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:15:04'));
+        $data = $this->createUserWithPermission([
+            'time-entries:view:own',
+        ]);
+        $timeEntry1 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:08'),
+                'end' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'),
+            ]);
+        $timeEntry2 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:07'),
+                'end' => null,
+            ]);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.time-entries.index', [
+            $data->organization->getKey(),
+            'member_id' => $data->member->getKey(),
+            'rounding_type' => TimeEntryRoundingType::Up,
+            'rounding_minutes' => 6,
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+        $response->assertJson(fn (AssertableJson $json) => $json
+            ->has('data')
+            ->has('meta')
+            ->where('meta.total', 2)
+            ->count('data', 2)
+            ->where('data.0.id', $timeEntry1->getKey())
+            ->where('data.0.start', '2020-01-01T00:00:00Z')
+            ->where('data.0.end', '2020-01-01T00:06:00Z')
+            ->where('data.1.id', $timeEntry2->getKey())
+            ->where('data.1.start', '2020-01-01T00:00:00Z')
+            ->where('data.1.end', '2020-01-01T00:18:00Z')
+        );
+    }
+
+    public function test_index_endpoint_can_round_down(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:15:04'));
+        $data = $this->createUserWithPermission([
+            'time-entries:view:own',
+        ]);
+        $timeEntry1 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:08'),
+                'end' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'),
+            ]);
+        $timeEntry2 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:07'),
+                'end' => null,
+            ]);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.time-entries.index', [
+            $data->organization->getKey(),
+            'member_id' => $data->member->getKey(),
+            'rounding_type' => TimeEntryRoundingType::Down,
+            'rounding_minutes' => 6,
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+        $response->assertJson(fn (AssertableJson $json) => $json
+            ->has('data')
+            ->has('meta')
+            ->where('meta.total', 2)
+            ->count('data', 2)
+            ->where('data.0.id', $timeEntry1->getKey())
+            ->where('data.0.start', '2020-01-01T00:00:00Z')
+            ->where('data.0.end', '2020-01-01T00:00:00Z')
+            ->where('data.1.id', $timeEntry2->getKey())
+            ->where('data.1.start', '2020-01-01T00:00:00Z')
+            ->where('data.1.end', '2020-01-01T00:12:00Z')
+        );
+    }
+
+    public function test_index_endpoint_can_round_nearest(): void
+    {
+        // Arrange
+        $this->travelTo(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:15:00'));
+        $data = $this->createUserWithPermission([
+            'time-entries:view:own',
+        ]);
+        $timeEntry1 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:08'),
+                'end' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:02:59'),
+            ]);
+        $timeEntry2 = TimeEntry::factory()->forOrganization($data->organization)
+            ->forMember($data->member)
+            ->create([
+                'start' => Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:07'),
+                'end' => null,
+            ]);
+        Passport::actingAs($data->user);
+
+        // Act
+        $response = $this->getJson(route('api.v1.time-entries.index', [
+            $data->organization->getKey(),
+            'member_id' => $data->member->getKey(),
+            'rounding_type' => TimeEntryRoundingType::Nearest,
+            'rounding_minutes' => 6,
+        ]));
+
+        // Assert
+        $this->assertResponseCode($response, 200);
+        $response->assertJson(fn (AssertableJson $json) => $json
+            ->has('data')
+            ->has('meta')
+            ->where('meta.total', 2)
+            ->count('data', 2)
+            ->where('data.0.id', $timeEntry1->getKey())
+            ->where('data.0.start', '2020-01-01T00:00:00Z')
+            ->where('data.0.end', '2020-01-01T00:00:00Z')
+            ->where('data.1.id', $timeEntry2->getKey())
+            ->where('data.1.start', '2020-01-01T00:00:00Z')
+            ->where('data.1.end', '2020-01-01T00:18:00Z')
+        );
+    }
+
     public function test_index_endpoint_after_filter_returns_time_entries_after_date(): void
     {
         // Arrange
diff --git a/tests/Unit/Service/TimeEntryAggregationServiceTest.php b/tests/Unit/Service/TimeEntryAggregationServiceTest.php
index 2b6009a2..b46291b1 100644
--- a/tests/Unit/Service/TimeEntryAggregationServiceTest.php
+++ b/tests/Unit/Service/TimeEntryAggregationServiceTest.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace Tests\Unit\Service;
 
 use App\Enums\TimeEntryAggregationType;
+use App\Enums\TimeEntryRoundingType;
 use App\Enums\Weekday;
 use App\Models\Client;
 use App\Models\Project;
@@ -40,7 +41,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             null,
             null,
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -87,7 +90,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             Carbon::now()->subDays(2)->utc(),
             Carbon::now()->subDay()->utc(),
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -172,7 +177,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             Carbon::now()->subDays(2)->utc(),
             Carbon::now()->subDay()->utc(),
-            false
+            false,
+            null,
+            null
         );
 
         // Assert
@@ -238,7 +245,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             true,
             Carbon::now()->subDays(2)->utc(),
             Carbon::now()->subDay()->utc(),
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -280,7 +289,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             true,
             Carbon::now()->subDays(2),
             Carbon::now()->subDay(),
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -307,7 +318,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             true,
             Carbon::now()->subDays(2),
             Carbon::now()->subDay(),
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -343,7 +356,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             null,
             null,
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -408,6 +423,302 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
         ], $result);
     }
 
+    public function test_aggregate_time_can_round_up_per_time_entry(): void
+    {
+        // Arrange
+        $client1 = Client::factory()->create();
+        $client2 = Client::factory()->create();
+        $project1 = Project::factory()->forClient($client1)->create();
+        $project2 = Project::factory()->forClient($client2)->create();
+        $project3 = Project::factory()->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 450)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 449)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 451)
+            ->forProject($project2)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 450)
+            ->forProject($project3)
+            ->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 449)
+            ->create();
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Client,
+            TimeEntryAggregationType::Project,
+            'Europe/Vienna',
+            Weekday::Monday,
+            false,
+            null,
+            null,
+            true,
+            TimeEntryRoundingType::Up,
+            15
+        );
+
+        // Assert
+        $this->assertEqualsCanonicalizing([
+            'seconds' => 4500,
+            'cost' => 0,
+            'grouped_type' => 'client',
+            'grouped_data' => [
+                [
+                    'key' => null,
+                    'seconds' => 1800,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => null,
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                        [
+                            'key' => $project3->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client1->getKey(),
+                    'seconds' => 1800,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project1->getKey(),
+                            'seconds' => 1800,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client2->getKey(),
+                    'seconds' => 900,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project2->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+            ],
+        ], $result);
+    }
+
+    public function test_aggregate_time_can_round_down_per_time_entry(): void
+    {
+        // Arrange
+        $client1 = Client::factory()->create();
+        $client2 = Client::factory()->create();
+        $project1 = Project::factory()->forClient($client1)->create();
+        $project2 = Project::factory()->forClient($client2)->create();
+        $project3 = Project::factory()->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 450)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 449)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 451)
+            ->forProject($project2)->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 900 + 450)
+            ->forProject($project3)
+            ->create();
+        TimeEntry::factory()->endWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:01'), 900 + 449)
+            ->create();
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Client,
+            TimeEntryAggregationType::Project,
+            'Europe/Vienna',
+            Weekday::Monday,
+            false,
+            null,
+            null,
+            true,
+            TimeEntryRoundingType::Down,
+            15
+        );
+
+        // Assert
+        $this->assertEqualsCanonicalizing([
+            'seconds' => 1800,
+            'cost' => 0,
+            'grouped_type' => 'client',
+            'grouped_data' => [
+                [
+                    'key' => null,
+                    'seconds' => 1800,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => null,
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                        [
+                            'key' => $project3->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client1->getKey(),
+                    'seconds' => 0,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project1->getKey(),
+                            'seconds' => 0,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client2->getKey(),
+                    'seconds' => 0,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project2->getKey(),
+                            'seconds' => 0,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+            ],
+        ], $result);
+    }
+
+    public function test_aggregate_time_can_round_to_nearest_per_time_entry(): void
+    {
+        // Arrange
+        $client1 = Client::factory()->create();
+        $client2 = Client::factory()->create();
+        $project1 = Project::factory()->forClient($client1)->create();
+        $project2 = Project::factory()->forClient($client2)->create();
+        $project3 = Project::factory()->create();
+        TimeEntry::factory()->startWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:00'), 449)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->startWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:00'), 450)
+            ->forProject($project1)->create();
+        TimeEntry::factory()->startWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:00'), 450)
+            ->forProject($project2)->create();
+        TimeEntry::factory()->startWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:00'), 450)
+            ->forProject($project3)
+            ->create();
+        TimeEntry::factory()->startWithDuration(Carbon::createFromFormat('Y-m-d H:i:s', '2020-01-01 00:00:00'), 450)
+            ->create();
+        $query = TimeEntry::query();
+
+        // Act
+        $result = $this->service->getAggregatedTimeEntries(
+            $query,
+            TimeEntryAggregationType::Client,
+            TimeEntryAggregationType::Project,
+            'Europe/Vienna',
+            Weekday::Monday,
+            false,
+            null,
+            null,
+            true,
+            TimeEntryRoundingType::Nearest,
+            15
+        );
+
+        // Assert
+        $this->assertEqualsCanonicalizing([
+            'seconds' => 3600,
+            'cost' => 0,
+            'grouped_type' => 'client',
+            'grouped_data' => [
+                [
+                    'key' => null,
+                    'seconds' => 1800,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => null,
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                        [
+                            'key' => $project3->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client1->getKey(),
+                    'seconds' => 900,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project1->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+                [
+                    'key' => $client2->getKey(),
+                    'seconds' => 900,
+                    'cost' => 0,
+                    'grouped_type' => 'project',
+                    'grouped_data' => [
+                        [
+                            'key' => $project2->getKey(),
+                            'seconds' => 900,
+                            'cost' => 0,
+                            'grouped_type' => null,
+                            'grouped_data' => null,
+                        ],
+                    ],
+                ],
+            ],
+        ], $result);
+    }
+
+    // TODO: test with 1 minute
+
     public function test_aggregate_time_entries_by_client_and_project_with_filled_gaps(): void
     {
         // Arrange
@@ -432,7 +743,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             true,
             null,
             null,
-            true
+            true,
+            null,
+            null
         );
 
         // Assert
@@ -528,7 +841,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             null,
             null,
-            true
+            true,
+            null,
+            null,
         );
 
         // Assert
@@ -612,7 +927,9 @@ class TimeEntryAggregationServiceTest extends TestCaseWithDatabase
             false,
             null,
             null,
-            true
+            true,
+            null,
+            null,
         );
 
         // Assert