diff --git a/src/Export/Base/CsvRenderer.php b/src/Export/Base/CsvRenderer.php
index b54bcb5c..83f76779 100644
--- a/src/Export/Base/CsvRenderer.php
+++ b/src/Export/Base/CsvRenderer.php
@@ -11,6 +11,7 @@ namespace App\Export\Base;
 
 use App\Entity\ExportableItem;
 use App\Export\ExportFilename;
+use App\Export\Package\CellFormatter\DateStringFormatter;
 use App\Export\Package\SpoutSpreadsheet;
 use App\Export\RendererInterface;
 use App\Export\TimesheetExportInterface;
@@ -65,6 +66,7 @@ final class CsvRenderer implements RendererInterface, TimesheetExportInterface
         $spreadsheet = new SpoutSpreadsheet(new Writer($options));
         $spreadsheet->open($filename);
 
+        $this->spreadsheetRenderer->registerFormatter('date', new DateStringFormatter());
         $this->spreadsheetRenderer->writeSpreadsheet($spreadsheet, $exportItems, $query);
 
         return new \SplFileInfo($filename);
diff --git a/src/Export/Base/SpreadsheetRenderer.php b/src/Export/Base/SpreadsheetRenderer.php
index 3088b3ed..16e2f5a7 100644
--- a/src/Export/Base/SpreadsheetRenderer.php
+++ b/src/Export/Base/SpreadsheetRenderer.php
@@ -19,6 +19,7 @@ use App\Event\TimesheetMetaDisplayEvent;
 use App\Event\UserPreferenceDisplayEvent;
 use App\Export\Package\CellFormatter\ArrayFormatter;
 use App\Export\Package\CellFormatter\BooleanFormatter;
+use App\Export\Package\CellFormatter\CellFormatterInterface;
 use App\Export\Package\CellFormatter\DateFormatter;
 use App\Export\Package\CellFormatter\DefaultFormatter;
 use App\Export\Package\CellFormatter\DurationFormatter;
@@ -40,6 +41,11 @@ use Symfony\Contracts\Translation\TranslatorInterface;
  */
 final class SpreadsheetRenderer
 {
+    /**
+     * @var array<string, CellFormatterInterface>
+     */
+    private array $formatter = [];
+
     public function __construct(
         protected TranslatorInterface $translator,
         protected EventDispatcherInterface $dispatcher,
@@ -115,6 +121,25 @@ final class SpreadsheetRenderer
         $spreadsheetPackage->save();
     }
 
+    public function registerFormatter(string $name, CellFormatterInterface $cellFormatter): void
+    {
+        $this->formatter[$name] = $cellFormatter;
+    }
+
+    private function getFormatter(string $name): CellFormatterInterface
+    {
+        if (\array_key_exists($name, $this->formatter)) {
+            return $this->formatter[$name];
+        }
+
+        return match ($name) {
+            'date' => new DateFormatter(),
+            'time' => new TimeFormatter(),
+            'duration' => new DurationFormatter(),
+            default => new DefaultFormatter()
+        };
+    }
+
     /**
      * @return array<Column>
      */
@@ -124,40 +149,40 @@ final class SpreadsheetRenderer
 
         $columns = [];
 
-        $columns[] = (new Column('date', new DateFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getBegin());
-        $columns[] = (new Column('begin', new TimeFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getBegin());
-        $columns[] = (new Column('end', new TimeFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getEnd());
-        $columns[] = (new Column('duration', new DurationFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getDuration());
+        $columns[] = (new Column('date', $this->getFormatter('date')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getBegin());
+        $columns[] = (new Column('begin', $this->getFormatter('time')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getBegin());
+        $columns[] = (new Column('end', $this->getFormatter('time')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getEnd());
+        $columns[] = (new Column('duration', $this->getFormatter('duration')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getDuration());
 
         if ($showRates) {
-            $columns[] = (new Column('currency', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getCurrency());
+            $columns[] = (new Column('currency', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getCurrency());
             $columns[] = (new Column('rate', new RateFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getRate());
             $columns[] = (new Column('internalRate', new RateFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getInternalRate());
             $columns[] = (new Column('hourlyRate', new RateFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getHourlyRate());
             $columns[] = (new Column('fixedRate', new RateFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getFixedRate());
         }
 
-        $columns[] = (new Column('username', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getUser()?->getDisplayName());
-        $columns[] = (new Column('account_number', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getUser()?->getAccountNumber());
-        $columns[] = (new Column('customer', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getName());
-        $columns[] = (new Column('project', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getName());
-        $columns[] = (new Column('activity', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getActivity()?->getName());
+        $columns[] = (new Column('username', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getUser()?->getDisplayName());
+        $columns[] = (new Column('account_number', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getUser()?->getAccountNumber());
+        $columns[] = (new Column('customer', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getName());
+        $columns[] = (new Column('project', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getName());
+        $columns[] = (new Column('activity', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getActivity()?->getName());
         $columns[] = (new Column('description', new TextFormatter(true)))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getDescription());
         //$columns[] = (new Column('exported', new BooleanFormatter()))->withExtractor(fn(ExportableItem $exportableItem) => $exportableItem->isExported());
         $columns[] = (new Column('billable', new BooleanFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->isBillable());
         $columns[] = (new Column('tags', new ArrayFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getTagsAsArray());
-        $columns[] = (new Column('type', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getType());
-        $columns[] = (new Column('category', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getCategory());
-        $columns[] = (new Column('number', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getNumber());
-        $columns[] = (new Column('project_number', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getNumber());
-        $columns[] = (new Column('vat_id', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getVatId());
-        $columns[] = (new Column('orderNumber', new DefaultFormatter()))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getOrderNumber());
+        $columns[] = (new Column('type', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getType());
+        $columns[] = (new Column('category', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getCategory());
+        $columns[] = (new Column('number', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getNumber());
+        $columns[] = (new Column('project_number', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getNumber());
+        $columns[] = (new Column('vat_id', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getCustomer()?->getVatId());
+        $columns[] = (new Column('orderNumber', $this->getFormatter('default')))->withExtractor(fn (ExportableItem $exportableItem) => $exportableItem->getProject()?->getOrderNumber());
 
         foreach ($this->findMetaColumns(new TimesheetMetaDisplayEvent($query, TimesheetMetaDisplayEvent::EXPORT)) as $metaField) {
             if ($metaField->getName() === null) {
                 continue;
             }
-            $columns[] = (new Column('timesheet.meta.' . $metaField->getName(), new DefaultFormatter()))
+            $columns[] = (new Column('timesheet.meta.' . $metaField->getName(), $this->getFormatter('default')))
                 ->withHeader($metaField->getLabel())
                 ->withExtractor(function (ExportableItem $exportableItem) use ($metaField) {
                     return $exportableItem->getMetaField($metaField->getName())?->getValue();
@@ -168,7 +193,7 @@ final class SpreadsheetRenderer
             if ($metaField->getName() === null) {
                 continue;
             }
-            $columns[] = (new Column('customer.meta.' . $metaField->getName(), new DefaultFormatter()))
+            $columns[] = (new Column('customer.meta.' . $metaField->getName(), $this->getFormatter('default')))
                 ->withHeader($metaField->getLabel())
                 ->withExtractor(function (ExportableItem $exportableItem) use ($metaField) {
                     return $exportableItem->getProject()?->getCustomer()?->getMetaField($metaField->getName())?->getValue();
@@ -179,7 +204,7 @@ final class SpreadsheetRenderer
             if ($metaField->getName() === null) {
                 continue;
             }
-            $columns[] = (new Column('project.meta.' . $metaField->getName(), new DefaultFormatter()))
+            $columns[] = (new Column('project.meta.' . $metaField->getName(), $this->getFormatter('default')))
                 ->withHeader($metaField->getLabel())
                 ->withExtractor(function (ExportableItem $exportableItem) use ($metaField) {
                     return $exportableItem->getProject()?->getMetaField($metaField->getName())?->getValue();
@@ -190,7 +215,7 @@ final class SpreadsheetRenderer
             if ($metaField->getName() === null) {
                 continue;
             }
-            $columns[] = (new Column('activity.meta.' . $metaField->getName(), new DefaultFormatter()))
+            $columns[] = (new Column('activity.meta.' . $metaField->getName(), $this->getFormatter('default')))
                 ->withHeader($metaField->getLabel())
                 ->withExtractor(function (ExportableItem $exportableItem) use ($metaField) {
                     return $exportableItem->getActivity()?->getMetaField($metaField->getName())?->getValue();
@@ -203,7 +228,7 @@ final class SpreadsheetRenderer
             if ($metaField->getName() === null) {
                 continue;
             }
-            $columns[] = (new Column('user.meta.' . $metaField->getName(), new DefaultFormatter()))
+            $columns[] = (new Column('user.meta.' . $metaField->getName(), $this->getFormatter('default')))
                 ->withHeader($metaField->getLabel())
                 ->withExtractor(function (ExportableItem $exportableItem) use ($metaField) {
                     return $exportableItem->getUser()?->getPreference($metaField->getName())?->getValue();
diff --git a/src/Export/Package/CellFormatter/DateFormatter.php b/src/Export/Package/CellFormatter/DateFormatter.php
index 22f029f1..3240070d 100644
--- a/src/Export/Package/CellFormatter/DateFormatter.php
+++ b/src/Export/Package/CellFormatter/DateFormatter.php
@@ -14,7 +14,7 @@ final class DateFormatter implements CellFormatterInterface
     public function formatValue(mixed $value): mixed
     {
         if ($value instanceof \DateTimeInterface) {
-            return $value->format('Y-m-d');
+            return $value;
         }
 
         if ($value === null) {
diff --git a/src/Export/Package/CellFormatter/DateStringFormatter.php b/src/Export/Package/CellFormatter/DateStringFormatter.php
new file mode 100644
index 00000000..bd92b04b
--- /dev/null
+++ b/src/Export/Package/CellFormatter/DateStringFormatter.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Export\Package\CellFormatter;
+
+final class DateStringFormatter implements CellFormatterInterface
+{
+    public function formatValue(mixed $value): mixed
+    {
+        if ($value instanceof \DateTimeInterface) {
+            return $value->format('Y-m-d');
+        }
+
+        if ($value === null) {
+            return null;
+        }
+
+        throw new \InvalidArgumentException('Only DateTimeInterface can be formatted');
+    }
+}
diff --git a/src/Export/Package/SpoutSpreadsheet.php b/src/Export/Package/SpoutSpreadsheet.php
index ecc0eff8..1c836e2c 100644
--- a/src/Export/Package/SpoutSpreadsheet.php
+++ b/src/Export/Package/SpoutSpreadsheet.php
@@ -23,9 +23,12 @@ use OpenSpout\Writer\XLSX\Entity\SheetView;
 
 class SpoutSpreadsheet implements SpreadsheetPackage
 {
+    private Style $dateStyle;
+
     public function __construct(private readonly WriterInterface $writer)
     {
         $this->writer->setCreator(Constants::SOFTWARE);
+        $this->dateStyle = (new Style())->setFormat('yyyy-mm-dd');
     }
 
     /**
@@ -68,7 +71,11 @@ class SpoutSpreadsheet implements SpreadsheetPackage
 
         $tmp = [];
         foreach ($columns as $column) {
-            $tmp[] = Cell::fromValue($column); // @phpstan-ignore argument.type
+            if ($column instanceof \DateTimeInterface) {
+                $tmp[] = Cell::fromValue($column, $this->dateStyle);
+            } else {
+                $tmp[] = Cell::fromValue($column); // @phpstan-ignore argument.type
+            }
         }
 
         $this->writer->addRow(new Row($tmp, $style));
diff --git a/tests/Export/Package/CellFormatter/DateFormatterTest.php b/tests/Export/Package/CellFormatter/DateFormatterTest.php
index a9ae5c79..1882c176 100644
--- a/tests/Export/Package/CellFormatter/DateFormatterTest.php
+++ b/tests/Export/Package/CellFormatter/DateFormatterTest.php
@@ -22,7 +22,7 @@ class DateFormatterTest extends TestCase
         $formatter = new DateFormatter();
         $date = new \DateTime('2023-10-01');
         $result = $formatter->formatValue($date);
-        self::assertEquals('2023-10-01', $result);
+        $this->assertInstanceOf(\DateTimeInterface::class, $result);
     }
 
     public function testFormatValueReturnsNullForNullValue(): void
diff --git a/tests/Export/Package/CellFormatter/DateStringFormatterTest.php b/tests/Export/Package/CellFormatter/DateStringFormatterTest.php
new file mode 100644
index 00000000..12939360
--- /dev/null
+++ b/tests/Export/Package/CellFormatter/DateStringFormatterTest.php
@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Export\Package\CellFormatter;
+
+use App\Export\Package\CellFormatter\DateStringFormatter;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \App\Export\Package\CellFormatter\DateStringFormatter
+ */
+class DateStringFormatterTest extends TestCase
+{
+    public function testFormatValueReturnsFormattedDateForDateTime(): void
+    {
+        $formatter = new DateStringFormatter();
+        $date = new \DateTime('2023-10-01 12:37');
+        $result = $formatter->formatValue($date);
+        $this->assertIsString($result);
+        $this->assertEquals('2023-10-01', $result);
+    }
+
+    public function testFormatValueReturnsNullForNullValue(): void
+    {
+        $formatter = new DateStringFormatter();
+        $result = $formatter->formatValue(null);
+        self::assertNull($result);
+    }
+
+    public function testFormatValueThrowsExceptionForNonDateTime(): void
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Only DateTimeInterface can be formatted');
+
+        $formatter = new DateStringFormatter();
+        $formatter->formatValue('not a date');
+    }
+}