diff --git a/apps/client/src/translations/en/translation.json b/apps/client/src/translations/en/translation.json
index 49090efa7..0d962270d 100644
--- a/apps/client/src/translations/en/translation.json
+++ b/apps/client/src/translations/en/translation.json
@@ -1424,7 +1424,8 @@
     "min-days-in-first-week": "Minimum days in first week",
     "first-week-info": "First week contains first Thursday of the year is based on <a href=\"https://en.wikipedia.org/wiki/ISO_week_date#First_week\">ISO 8601</a> standard.",
     "first-week-warning": "Changing first week options may cause duplicate with existing Week Notes and the existing Week Notes will not be updated accordingly.",
-    "formatting-locale": "Date & number format"
+    "formatting-locale": "Date & number format",
+    "formatting-locale-auto": "Based on the application's language"
   },
   "backup": {
     "automatic_backup": "Automatic backup",
diff --git a/apps/client/src/utils/formatters.ts b/apps/client/src/utils/formatters.ts
index 664580c65..40f97e673 100644
--- a/apps/client/src/utils/formatters.ts
+++ b/apps/client/src/utils/formatters.ts
@@ -10,7 +10,7 @@ export function formatDateTime(date: string | Date | number | null | undefined,
         return "";
     }
 
-    const locale = options.get("formattingLocale") ?? options.get("locale") ?? navigator.language;
+    const locale = options.get("formattingLocale") || options.get("locale") || navigator.language;
 
     let parsedDate;
     if (typeof date === "string" || typeof date === "number") {
diff --git a/apps/client/src/widgets/type_widgets/options/i18n.tsx b/apps/client/src/widgets/type_widgets/options/i18n.tsx
index 9ebca626b..1084a05a8 100644
--- a/apps/client/src/widgets/type_widgets/options/i18n.tsx
+++ b/apps/client/src/widgets/type_widgets/options/i18n.tsx
@@ -23,7 +23,7 @@ export default function InternationalizationOptions() {
 }
 
 function LocalizationOptions() {
-    const { uiLocales, formattingLocales: contentLocales } = useMemo(() => {
+    const { uiLocales, formattingLocales: contentLocales } = useMemo<{ uiLocales: Locale[], formattingLocales: Locale[] }>(() => {
         const allLocales = getAvailableLocales();
         return {
             uiLocales: allLocales.filter(locale => {
@@ -31,7 +31,10 @@ function LocalizationOptions() {
                 if (locale.devOnly && !glob.isDev) return false;
                 return true;
             }),
-            formattingLocales: allLocales.filter(locale => locale.electronLocale),
+            formattingLocales: [
+                { id: "", name: t("i18n.formatting-locale-auto") },
+                ...allLocales.filter(locale => locale.electronLocale)
+            ]
         }
     }, []);
 
diff --git a/apps/desktop/src/main.ts b/apps/desktop/src/main.ts
index 000d4c458..52ebe458b 100644
--- a/apps/desktop/src/main.ts
+++ b/apps/desktop/src/main.ts
@@ -30,7 +30,7 @@ async function main() {
 
     // needed for excalidraw export https://github.com/zadam/trilium/issues/4271
     app.commandLine.appendSwitch("enable-experimental-web-platform-features");
-    app.commandLine.appendSwitch("lang", options.getOptionOrNull("formattingLocale") ?? "en");
+    app.commandLine.appendSwitch("lang", options.getOptionOrNull("formattingLocale") || options.getOptionOrNull("locale") || "en");
 
     // Disable smooth scroll if the option is set
     const smoothScrollEnabled = options.getOptionOrNull("smoothScrollEnabled");
diff --git a/apps/server/src/services/options_init.ts b/apps/server/src/services/options_init.ts
index 0908a0512..c6e0231c5 100644
--- a/apps/server/src/services/options_init.ts
+++ b/apps/server/src/services/options_init.ts
@@ -159,7 +159,7 @@ const defaultOptions: DefaultOption[] = [
 
     // Internationalization
     { name: "locale", value: "en", isSynced: true },
-    { name: "formattingLocale", value: "en", isSynced: true },
+    { name: "formattingLocale", value: "", isSynced: true }, // no value means auto-detect
     { name: "firstDayOfWeek", value: "1", isSynced: true },
     { name: "firstWeekOfYear", value: "0", isSynced: true },
     { name: "minDaysInFirstWeek", value: "4", isSynced: true },