diff --git a/src/Spout/Common/Helper/StringHelper.php b/src/Spout/Common/Helper/StringHelper.php
index 0906132..6256b1e 100644
--- a/src/Spout/Common/Helper/StringHelper.php
+++ b/src/Spout/Common/Helper/StringHelper.php
@@ -13,12 +13,20 @@ class StringHelper
     /** @var bool Whether the mbstring extension is loaded */
     protected $hasMbstringSupport;
 
+    /** @var bool Whether the code is running with PHP7 or older versions */
+    private $isRunningPhp7OrOlder;
+
+    /** @var array Locale info, used for number formatting */
+    private $localeInfo;
+
     /**
      *
      */
     public function __construct()
     {
         $this->hasMbstringSupport = \extension_loaded('mbstring');
+        $this->isRunningPhp7OrOlder = \version_compare(PHP_VERSION, '8.0.0') < 0;
+        $this->localeInfo = \localeconv();
     }
 
     /**
@@ -68,4 +76,30 @@ class StringHelper
 
         return ($position !== false) ? $position : -1;
     }
+
+    /**
+     * Formats a numeric value (int or float) in a way that's compatible with the expected spreadsheet format.
+     *
+     * Formatting of float values is locale dependent in PHP < 8.
+     * Thousands separators and decimal points vary from locale to locale (en_US: 12.34 vs pl_PL: 12,34).
+     * However, float values must be formatted with no thousands separator and a "." as decimal point
+     * to work properly. This method can be used to convert the value to the correct format before storing it.
+     *
+     * @see https://wiki.php.net/rfc/locale_independent_float_to_string for the changed behavior in PHP8.
+     *
+     * @param int|float $numericValue
+     * @return string
+     */
+    public function formatNumericValue($numericValue)
+    {
+        if ($this->isRunningPhp7OrOlder && is_float($numericValue)) {
+            return str_replace(
+                [$this->localeInfo['thousands_sep'], $this->localeInfo['decimal_point']],
+                ['', '.'],
+                $numericValue
+            );
+        }
+
+        return $numericValue;
+    }
 }
diff --git a/src/Spout/Writer/ODS/Manager/WorksheetManager.php b/src/Spout/Writer/ODS/Manager/WorksheetManager.php
index e0366d1..7d7cb0e 100644
--- a/src/Spout/Writer/ODS/Manager/WorksheetManager.php
+++ b/src/Spout/Writer/ODS/Manager/WorksheetManager.php
@@ -231,8 +231,9 @@ class WorksheetManager implements WorksheetManagerInterface
             $data .= '<text:p>' . $cell->getValue() . '</text:p>';
             $data .= '</table:table-cell>';
         } elseif ($cell->isNumeric()) {
-            $data .= ' office:value-type="float" calcext:value-type="float" office:value="' . $cell->getValue() . '">';
-            $data .= '<text:p>' . $cell->getValue() . '</text:p>';
+            $cellValue = $this->stringHelper->formatNumericValue($cell->getValue());
+            $data .= ' office:value-type="float" calcext:value-type="float" office:value="' . $cellValue . '">';
+            $data .= '<text:p>' . $cellValue . '</text:p>';
             $data .= '</table:table-cell>';
         } elseif ($cell->isError() && is_string($cell->getValueEvenIfError())) {
             // only writes the error value if it's a string
diff --git a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
index 028bdef..61b93a1 100644
--- a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
+++ b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
@@ -240,7 +240,7 @@ EOD;
         } elseif ($cell->isBoolean()) {
             $cellXML .= ' t="b"><v>' . (int) ($cell->getValue()) . '</v></c>';
         } elseif ($cell->isNumeric()) {
-            $cellXML .= '><v>' . $cell->getValue() . '</v></c>';
+            $cellXML .= '><v>' . $this->stringHelper->formatNumericValue($cell->getValue()) . '</v></c>';
         } elseif ($cell->isError() && is_string($cell->getValueEvenIfError())) {
             // only writes the error value if it's a string
             $cellXML .= ' t="e"><v>' . $cell->getValueEvenIfError() . '</v></c>';
diff --git a/tests/Spout/Writer/ODS/WriterTest.php b/tests/Spout/Writer/ODS/WriterTest.php
index 31dcccf..61c1b9e 100644
--- a/tests/Spout/Writer/ODS/WriterTest.php
+++ b/tests/Spout/Writer/ODS/WriterTest.php
@@ -279,6 +279,52 @@ class WriterTest extends TestCase
         $this->assertValueWasWrittenToSheet($fileName, 1, 10.2);
     }
 
+    /**
+     * @return void
+     */
+    public function testAddRowShouldSupportFloatValuesInDifferentLocale()
+    {
+        $previousLocale = \setlocale(LC_ALL, 0);
+
+        try {
+            // Pick a supported locale whose decimal point is a comma.
+            // Installed locales differ from one system to another, so we can't pick
+            // a given locale.
+            $supportedLocales = explode("\n", shell_exec('locale -a'));
+            foreach ($supportedLocales as $supportedLocale) {
+                \setlocale(LC_ALL, $supportedLocale);
+                if (\localeconv()['decimal_point'] === ',') {
+                    break;
+                }
+            }
+            $this->assertEquals(',', \localeconv()['decimal_point']);
+
+            $cellValue = 1234.5;
+            var_dump("Cell value before: " . $cellValue);
+            $cellValue = str_replace(
+                [\localeconv()['thousands_sep'], \localeconv()['decimal_point']],
+                ['', '.'],
+                $cellValue
+            );
+            var_dump("Cell value after: " . $cellValue);
+            var_dump("Thousands sep: " . \localeconv()['thousands_sep']);
+            var_dump("Decimal point: " . \localeconv()['decimal_point']);
+
+            $fileName = 'test_add_row_should_support_float_values_in_different_locale.xlsx';
+            $dataRows = $this->createRowsFromValues([
+                [1234.5],
+            ]);
+
+            $this->writeToODSFile($dataRows, $fileName);
+
+            $this->assertValueWasNotWrittenToSheet($fileName, 1, "1234,5");
+            $this->assertValueWasWrittenToSheet($fileName, 1, "1234.5");
+        } finally {
+            // reset locale
+            \setlocale(LC_ALL, $previousLocale);
+        }
+    }
+
     /**
      * @return array
      */
diff --git a/tests/Spout/Writer/XLSX/WriterTest.php b/tests/Spout/Writer/XLSX/WriterTest.php
index 9cc157a..e2a8e4e 100644
--- a/tests/Spout/Writer/XLSX/WriterTest.php
+++ b/tests/Spout/Writer/XLSX/WriterTest.php
@@ -393,6 +393,52 @@ class WriterTest extends TestCase
         $this->assertInlineDataWasWrittenToSheet($fileName, 1, 't="e"><v>#DIV/0</v>');
     }
 
+    /**
+     * @return void
+     */
+    public function testAddRowShouldSupportFloatValuesInDifferentLocale()
+    {
+        $previousLocale = \setlocale(LC_ALL, 0);
+        $valueToWrite = 1234.5; // needs to be defined before changing the locale as PHP8 would expect 1234,5
+
+        try {
+            // Pick a supported locale whose decimal point is a comma.
+            // Installed locales differ from one system to another, so we can't pick
+            // a given locale.
+            $supportedLocales = explode("\n", shell_exec('locale -a'));
+            foreach ($supportedLocales as $supportedLocale) {
+                \setlocale(LC_ALL, $supportedLocale);
+                if (\localeconv()['decimal_point'] === ',') {
+                    break;
+                }
+            }
+            $this->assertEquals(',', \localeconv()['decimal_point']);
+
+            var_dump("Cell value before: " . $valueToWrite);
+            $cellValue = str_replace(
+                [\localeconv()['thousands_sep'], \localeconv()['decimal_point']],
+                ['', '.'],
+                $valueToWrite
+            );
+            var_dump("Cell value after: " . $cellValue);
+            var_dump("Thousands sep: " . \localeconv()['thousands_sep']);
+            var_dump("Decimal point: " . \localeconv()['decimal_point']);
+
+            $fileName = 'test_add_row_should_support_float_values_in_different_locale.xlsx';
+            $dataRows = $this->createRowsFromValues([
+                [$valueToWrite],
+            ]);
+
+            $this->writeToXLSXFile($dataRows, $fileName, $shouldUseInlineStrings = false);
+
+            $this->assertInlineDataWasNotWrittenToSheet($fileName, 1, "1234,5");
+            $this->assertInlineDataWasWrittenToSheet($fileName, 1, "1234.5");
+        } finally {
+            // reset locale
+            \setlocale(LC_ALL, $previousLocale);
+        }
+    }
+
     /**
      * @return void
      */