diff --git a/Classes/Event/Listener/UsageToolBarEventListener.php b/Classes/Event/Listener/UsageToolBarEventListener.php
index 2c35d3ea..d925be56 100644
--- a/Classes/Event/Listener/UsageToolBarEventListener.php
+++ b/Classes/Event/Listener/UsageToolBarEventListener.php
@@ -49,11 +49,14 @@ public function __invoke(SystemInformationToolbarCollectorEvent $systemInformati
             'LLL:EXT:wv_deepltranslate/Resources/Private/Language/locallang.xlf:usages.toolbar.message'
         );
 
-        $severity = $this->determineSeverity($usage->character->count, $usage->character->limit);
+        $severity = $this->usageService->determineSeverityForSystemInformation($usage->character->count, $usage->character->limit);
 
         $systemInformation->getToolbarItem()->addSystemInformation(
             $title,
-            sprintf($message, $this->formatNumber($usage->character->count), $this->formatNumber($usage->character->limit)),
+            sprintf(
+                $message,
+                $this->usageService->formatNumber($usage->character->count),
+                $this->usageService->formatNumber($usage->character->limit)),
             'actions-localize-deepl',
             $severity
         );
@@ -63,38 +66,4 @@ private function getLanguageService(): LanguageService
     {
         return $GLOBALS['LANG'];
     }
-
-    /**
-     * Make large API limits easier to read
-     *
-     * @param int $number Any large integer - 5000000
-     * @return string Formated, better readable string variant of the integer - 5.000.000
-     */
-    private function formatNumber(int $number): string
-    {
-        return number_format($number, 0, ',', '.');
-    }
-
-
-    /**
-     * Calculate the message severity based on the quota usage rate
-     *
-     * @param int $characterCount Already translated characters in the current billing period
-     * @param int $characterLimit Total character limit in the current billing period
-     * @return string Severity level
-     */
-    private function determineSeverity(int $characterCount, int $characterLimit): string
-    {
-        $quotaUtilization = ($characterCount / $characterLimit) * 100;
-        if ($quotaUtilization >= 100) {
-            return InformationStatus::STATUS_ERROR;
-        }
-        if ($quotaUtilization >= 98) {
-            return InformationStatus::STATUS_WARNING;
-        }
-        if ($quotaUtilization >= 90) {
-            return InformationStatus::STATUS_INFO;
-        }
-        return InformationStatus::STATUS_NOTICE;
-    }
 }
diff --git a/Classes/Hooks/UsageProcessAfterFinishHook.php b/Classes/Hooks/UsageProcessAfterFinishHook.php
index d5116d8d..bec49272 100644
--- a/Classes/Hooks/UsageProcessAfterFinishHook.php
+++ b/Classes/Hooks/UsageProcessAfterFinishHook.php
@@ -4,8 +4,10 @@
 
 namespace WebVision\WvDeepltranslate\Hooks;
 
+use TYPO3\CMS\Core\Authentication\BackendUserAuthentication;
 use TYPO3\CMS\Core\Core\Environment;
 use TYPO3\CMS\Core\DataHandling\DataHandler;
+use TYPO3\CMS\Core\Information\Typo3Version;
 use TYPO3\CMS\Core\Localization\LanguageService;
 use TYPO3\CMS\Core\Messaging\FlashMessage;
 use TYPO3\CMS\Core\Messaging\FlashMessageService;
@@ -46,7 +48,7 @@ public function processCmdmap_afterFinish(DataHandler $dataHandler): void
             'LLL:EXT:wv_deepltranslate/Resources/Private/Language/locallang.xlf:usages.flashmassage.limit.description'
         );
 
-        $severity = $this->determineSeverity($usage->character->count, $usage->character->limit);
+        $severity = $this->usageService->determineSeverity($usage->character->count, $usage->character->limit);
         // Reduce noise - Don't bother editors with low quota usage messages
         if ($severity === FlashMessage::NOTICE) {
             return;
@@ -57,7 +59,10 @@ public function processCmdmap_afterFinish(DataHandler $dataHandler): void
 
         $flashMessage = GeneralUtility::makeInstance(
             FlashMessage::class,
-            sprintf($message, $this->formatNumber($usage->character->count), $this->formatNumber($usage->character->limit)),
+            sprintf(
+                $message,
+                $this->usageService->formatNumber($usage->character->count) ?: $usage->character->count,
+                $this->usageService->formatNumber($usage->character->limit)) ?: $usage->character->limit,
             $title,
             $severity,
             true
@@ -70,37 +75,4 @@ private function getLanguageService(): LanguageService
     {
         return $GLOBALS['LANG'];
     }
-
-    /**
-     * Make large API limits easier to read
-     *
-     * @param int $number Any large integer - 5000000
-     * @return string Formated, better readable string variant of the integer - 5.000.000
-     */
-    private function formatNumber(int $number): string
-    {
-        return number_format($number, 0, ',', '.');
-    }
-
-    /**
-     * Calculate the message severity based on the quota usage rate
-     *
-     * @param int $characterCount Already translated characters in the current billing period
-     * @param int $characterLimit Total character limit in the current billing period
-     * @return int Severity level
-     */
-    private function determineSeverity(int $characterCount, int $characterLimit): int
-    {
-        $quotaUtilization = ($characterCount / $characterLimit) * 100;
-        if ($quotaUtilization >= 100) {
-            return FlashMessage::ERROR;
-        }
-        if ($quotaUtilization >= 98) {
-            return FlashMessage::WARNING;
-        }
-        if ($quotaUtilization >= 90) {
-            return FlashMessage::INFO;
-        }
-        return FlashMessage::NOTICE;
-    }
 }
diff --git a/Classes/Service/UsageService.php b/Classes/Service/UsageService.php
index 25b15658..77b6f6bc 100644
--- a/Classes/Service/UsageService.php
+++ b/Classes/Service/UsageService.php
@@ -5,6 +5,10 @@
 namespace WebVision\WvDeepltranslate\Service;
 
 use DeepL\Usage;
+use TYPO3\CMS\Backend\Toolbar\Enumeration\InformationStatus;
+use TYPO3\CMS\Core\Authentication\BackendUserAuthentication;
+use TYPO3\CMS\Core\Information\Typo3Version;
+use TYPO3\CMS\Core\Messaging\FlashMessage;
 use WebVision\WvDeepltranslate\ClientInterface;
 
 final class UsageService implements UsageServiceInterface
@@ -47,4 +51,76 @@ public function isTranslateLimitExceeded(): bool
         }
         return $usage->character->count >= $usage->character->limit;
     }
+
+    /**
+     * Make large API limits easier to read
+     *
+     * @param int $number Any large integer - 5000000
+     * @return string|false Formated, better readable string variant of the integer - 5.000.000
+     */
+    public function formatNumber(int $number)
+    {
+        // @todo typo3/cms-core:>=12 remove polyfill switch, as php-intl is
+        //       then a hard requirement and the polyfill is not needed
+        if ((new Typo3Version())->getMajorVersion() <= 12 && !extension_loaded('intl')) {
+            if (!class_exists(\NumberFormatter::class)) {
+                return number_format($number);
+            }
+            // TYPO3 v11 has a Symfony Polyfill, but this ony allows
+            // locale en or null, so we call with default parameter.
+            $numberFormatter = new \NumberFormatter('en', \NumberFormatter::DECIMAL);
+        } else {
+            $language = 'en';
+            if ($this->getBackendUser() !== null) {
+                $uc = $this->getBackendUser()->uc;
+                if (is_array($uc) && array_key_exists('lang', $uc)) {
+                    $language = $uc['lang'];
+                }
+            }
+            $numberFormatter = new \NumberFormatter($language, \NumberFormatter::DECIMAL);
+        }
+        return $numberFormatter->format($number);
+    }
+
+    /**
+     * Calculate the message severity based on the quota usage rate
+     *
+     * @param int $characterCount Already translated characters in the current billing period
+     * @param int $characterLimit Total character limit in the current billing period
+     * @return int Severity level
+     */
+    public function determineSeverity(int $characterCount, int $characterLimit): int
+    {
+        $quotaUtilization = ($characterCount / $characterLimit) * 100;
+        if ($quotaUtilization >= 100) {
+            return FlashMessage::ERROR;
+        }
+        if ($quotaUtilization >= 98) {
+            return FlashMessage::WARNING;
+        }
+        if ($quotaUtilization >= 90) {
+            return FlashMessage::INFO;
+        }
+        return FlashMessage::NOTICE;
+    }
+
+    public function determineSeverityForSystemInformation(int $characterCount, int $characterLimit): string
+    {
+        $quotaUtilization = ($characterCount / $characterLimit) * 100;
+        if ($quotaUtilization >= 100) {
+            return InformationStatus::STATUS_ERROR;
+        }
+        if ($quotaUtilization >= 98) {
+            return InformationStatus::STATUS_WARNING;
+        }
+        if ($quotaUtilization >= 90) {
+            return InformationStatus::STATUS_INFO;
+        }
+        return InformationStatus::STATUS_NOTICE;
+    }
+
+    private function getBackendUser(): ?BackendUserAuthentication
+    {
+        return $GLOBALS['BE_USER'] ?? null;
+    }
 }