diff --git a/i18n/messages/ar.json b/i18n/messages/ar.json
index 587ff423..017a3df4 100644
--- a/i18n/messages/ar.json
+++ b/i18n/messages/ar.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "اللغة",
   "settings_label_timezone": "المنطقة الزمنية",
   "settings_label_currency": "العملة",
+  "settings_label_week_start_day": "أول يوم في الأسبوع",
   "settings_label_unit_distance": "وحدة المسافة",
   "settings_label_unit_volume": "وحدة الحجم",
   "settings_label_theme": "المظهر",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "اختر اللغة للواجهة",
   "settings_desc_timezone": "اختر منطقتك الزمنية لعرض التاريخ",
   "settings_desc_currency": "اختر العملة المفضلة لديك",
+  "settings_desc_week_start_day": "اختر أول يوم يظهر في التقويمات",
   "settings_desc_unit_distance": "قياس وحدة المسافة",
   "settings_desc_unit_volume": "قياس وحدة الحجم",
   "settings_label_mileage_format": "تنسيق عرض استهلاك الوقود",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "اختر المظهر المفضل لديك",
   "settings_desc_custom_css": "أنماط CSS لتخصيص الواجهة",
   "settings_select_language": "اختر اللغة",
+  "settings_select_week_start_day": "اختر أول يوم",
+  "settings_week_start_language_default": "افتراضي اللغة",
   "settings_updated_success": "تم تحديث الإعدادات بنجاح!",
   "common_example_prefix": "مثال - ",
   "common_invalid_format": "صيغة غير صحيحة...",
@@ -54,6 +58,13 @@
   "common_mile": "ميل",
   "common_litre": "لتر",
   "common_gallon": "جالون",
+  "common_sunday": "الأحد",
+  "common_monday": "الاثنين",
+  "common_tuesday": "الثلاثاء",
+  "common_wednesday": "الأربعاء",
+  "common_thursday": "الخميس",
+  "common_friday": "الجمعة",
+  "common_saturday": "السبت",
   "common_submit": "إرسال",
   "common_yes": "نعم",
   "common_no": "لا",
diff --git a/i18n/messages/cs.json b/i18n/messages/cs.json
index 3802f4b5..78fef1fb 100644
--- a/i18n/messages/cs.json
+++ b/i18n/messages/cs.json
@@ -37,6 +37,7 @@
   "settings_label_locale": "Jazyková verze",
   "settings_label_timezone": "Časové pásmo",
   "settings_label_currency": "Měna",
+  "settings_label_week_start_day": "První den týdne",
   "settings_label_unit_distance": "Jednotka vzdálenosti",
   "settings_label_unit_volume": "Jednotka paliva",
   "settings_label_theme": "Motiv",
@@ -50,6 +51,7 @@
   "settings_desc_locale": "Vyberte jazyk rozhraní",
   "settings_desc_timezone": "Vyberte časové pásmo pro zobrazení data",
   "settings_desc_currency": "Vyberte preferovanou měnu",
+  "settings_desc_week_start_day": "Vyberte první den zobrazený v kalendářích",
   "settings_desc_unit_distance": "Jednotka měření vzdálenosti",
   "settings_desc_unit_volume": "Jednotka měření objemu",
   "settings_label_mileage_format": "Formát zobrazení spotřeby",
@@ -61,6 +63,8 @@
   "settings_desc_dark_mode": "Vyberte styl kontrastu použitý v tmavém režimu",
   "settings_desc_custom_css": "Styly CSS pro úpravu rozhraní",
   "settings_select_language": "Vyberte jazyk",
+  "settings_select_week_start_day": "Vyberte první den",
+  "settings_week_start_language_default": "Výchozí podle jazyka",
   "settings_updated_success": "Nastavení bylo úspěšně aktualizováno!",
   "common_example_prefix": "Příklad – ",
   "common_invalid_format": "Neplatný formát...",
@@ -68,6 +72,13 @@
   "common_mile": "Míle",
   "common_litre": "Litr",
   "common_gallon": "Galon",
+  "common_sunday": "Neděle",
+  "common_monday": "Pondělí",
+  "common_tuesday": "Úterý",
+  "common_wednesday": "Středa",
+  "common_thursday": "Čtvrtek",
+  "common_friday": "Pátek",
+  "common_saturday": "Sobota",
   "common_submit": "Odeslat",
   "common_details": "Podrobnosti",
   "common_close": "Zavřít",
diff --git a/i18n/messages/de.json b/i18n/messages/de.json
index d8ad43a6..0037b216 100644
--- a/i18n/messages/de.json
+++ b/i18n/messages/de.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "Sprache",
   "settings_label_timezone": "Zeitzone",
   "settings_label_currency": "Währung",
+  "settings_label_week_start_day": "Erster Wochentag",
   "settings_label_unit_distance": "Entfernungseinheit",
   "settings_label_unit_volume": "Volumeneinheit",
   "settings_label_theme": "Design",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "Sprache der Oberfläche wählen",
   "settings_desc_timezone": "Zeitzone für Datumsanzeige wählen",
   "settings_desc_currency": "Bevorzugte Währung wählen",
+  "settings_desc_week_start_day": "Wählen Sie den ersten Tag, der in Kalendern angezeigt wird",
   "settings_desc_unit_distance": "Maßeinheit für Entfernung",
   "settings_desc_unit_volume": "Maßeinheit für Volumen",
   "settings_label_mileage_format": "Kraftstoffverbrauch-Anzeigeformat",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "Bevorzugtes Design wählen",
   "settings_desc_custom_css": "CSS-Stile zur Anpassung der Oberfläche",
   "settings_select_language": "Sprache auswählen",
+  "settings_select_week_start_day": "Ersten Tag auswählen",
+  "settings_week_start_language_default": "Sprachstandard",
   "settings_updated_success": "Konfiguration erfolgreich aktualisiert!",
   "common_example_prefix": "Beispiel - ",
   "common_invalid_format": "Ungültiges Format...",
@@ -54,6 +58,13 @@
   "common_mile": "Meilen",
   "common_litre": "Liter",
   "common_gallon": "Gallone",
+  "common_sunday": "Sonntag",
+  "common_monday": "Montag",
+  "common_tuesday": "Dienstag",
+  "common_wednesday": "Mittwoch",
+  "common_thursday": "Donnerstag",
+  "common_friday": "Freitag",
+  "common_saturday": "Samstag",
   "common_submit": "Senden",
   "common_yes": "Ja",
   "common_no": "Nein",
diff --git a/i18n/messages/en.json b/i18n/messages/en.json
index 888c28ef..a3e1b42f 100644
--- a/i18n/messages/en.json
+++ b/i18n/messages/en.json
@@ -37,6 +37,7 @@
   "settings_label_locale": "Locale",
   "settings_label_timezone": "Timezone",
   "settings_label_currency": "Currency",
+  "settings_label_week_start_day": "First day of week",
   "settings_label_unit_distance": "Unit of Distance",
   "settings_label_unit_volume": "Unit of Fuel",
   "settings_label_theme": "Theme",
@@ -50,6 +51,7 @@
   "settings_desc_locale": "Choose the language for the interface",
   "settings_desc_timezone": "Choose your timezone for date display",
   "settings_desc_currency": "Choose your preferred currency",
+  "settings_desc_week_start_day": "Choose the first day shown in calendars",
   "settings_desc_unit_distance": "Measurement of distance unit",
   "settings_desc_unit_volume": "Measurement of volume unit",
   "settings_label_mileage_format": "Mileage Display Format",
@@ -61,6 +63,8 @@
   "settings_desc_dark_mode": "Choose the contrast style used when dark mode is active",
   "settings_desc_custom_css": "CSS Styles for customizing the interface",
   "settings_select_language": "Select language",
+  "settings_select_week_start_day": "Select first day",
+  "settings_week_start_language_default": "Language default",
   "settings_updated_success": "Configuration updated successfully!",
   "common_example_prefix": "Example - ",
   "common_invalid_format": "Invalid Format...",
@@ -68,6 +72,13 @@
   "common_mile": "Miles",
   "common_litre": "Litre",
   "common_gallon": "Gallon",
+  "common_sunday": "Sunday",
+  "common_monday": "Monday",
+  "common_tuesday": "Tuesday",
+  "common_wednesday": "Wednesday",
+  "common_thursday": "Thursday",
+  "common_friday": "Friday",
+  "common_saturday": "Saturday",
   "common_submit": "Submit",
   "common_details": "Details",
   "common_close": "Close",
diff --git a/i18n/messages/es.json b/i18n/messages/es.json
index b00e3877..e1a1364a 100644
--- a/i18n/messages/es.json
+++ b/i18n/messages/es.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "Idioma",
   "settings_label_timezone": "Zona horaria",
   "settings_label_currency": "Moneda",
+  "settings_label_week_start_day": "Primer día de la semana",
   "settings_label_unit_distance": "Unidad de distancia",
   "settings_label_unit_volume": "Unidad de volumen",
   "settings_label_theme": "Tema",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "Elige el idioma de la interfaz",
   "settings_desc_timezone": "Elige tu zona horaria para mostrar fechas",
   "settings_desc_currency": "Elige tu moneda preferida",
+  "settings_desc_week_start_day": "Elige el primer día que se muestra en los calendarios",
   "settings_desc_unit_distance": "Unidad de medida de distancia",
   "settings_desc_unit_volume": "Unidad de medida de volumen",
   "settings_label_mileage_format": "Formato de visualización de consumo",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "Elige tu tema preferido",
   "settings_desc_custom_css": "Estilos CSS para personalizar la interfaz",
   "settings_select_language": "Selecciona el idioma",
+  "settings_select_week_start_day": "Selecciona el primer día",
+  "settings_week_start_language_default": "Predeterminado del idioma",
   "settings_updated_success": "¡Configuración actualizada con éxito!",
   "common_example_prefix": "Ejemplo - ",
   "common_invalid_format": "Formato no válido...",
@@ -54,6 +58,13 @@
   "common_mile": "Millas",
   "common_litre": "Litro",
   "common_gallon": "Galón",
+  "common_sunday": "Domingo",
+  "common_monday": "Lunes",
+  "common_tuesday": "Martes",
+  "common_wednesday": "Miércoles",
+  "common_thursday": "Jueves",
+  "common_friday": "Viernes",
+  "common_saturday": "Sábado",
   "common_submit": "Enviar",
   "common_yes": "Sí",
   "common_no": "No",
diff --git a/i18n/messages/fi.json b/i18n/messages/fi.json
index 8b33f634..69aae84b 100644
--- a/i18n/messages/fi.json
+++ b/i18n/messages/fi.json
@@ -28,6 +28,7 @@
   "settings_label_locale": "Kieli",
   "settings_label_timezone": "Aikavyöhyke",
   "settings_label_currency": "Valuutta",
+  "settings_label_week_start_day": "Viikon ensimmäinen päivä",
   "settings_label_unit_distance": "Etäisyyden yksikkö",
   "settings_label_unit_volume": "Polttoaineen yksikkö",
   "settings_label_theme": "Teema",
@@ -39,6 +40,7 @@
   "settings_desc_locale": "Valitse käyttöliittymän kieli",
   "settings_desc_timezone": "Valitse aikavyöhyke",
   "settings_desc_currency": "Valitse valuutta",
+  "settings_desc_week_start_day": "Valitse kalentereissa näytettävä ensimmäinen päivä",
   "settings_desc_unit_distance": "Etäisyyden mittayksikkö",
   "settings_desc_unit_volume": "Tilavuuden yksikkö",
   "settings_label_mileage_format": "Matkamittarin näyttömuoto",
@@ -49,6 +51,8 @@
   "settings_desc_theme": "Valitse teema",
   "settings_desc_custom_css": "CSS-tyylit käyttöliittymän mukauttamiseen",
   "settings_select_language": "Valitse kieli",
+  "settings_select_week_start_day": "Valitse ensimmäinen päivä",
+  "settings_week_start_language_default": "Kielen oletus",
   "settings_updated_success": "Asetukset päivitetty",
   "common_example_prefix": "Esimerkiksi - ",
   "common_invalid_format": "Virheellinen muoto",
@@ -56,6 +60,13 @@
   "common_mile": "Maili",
   "common_litre": "Litra",
   "common_gallon": "Gallona",
+  "common_sunday": "Sunnuntai",
+  "common_monday": "Maanantai",
+  "common_tuesday": "Tiistai",
+  "common_wednesday": "Keskiviikko",
+  "common_thursday": "Torstai",
+  "common_friday": "Perjantai",
+  "common_saturday": "Lauantai",
   "common_submit": "Tallenna",
   "common_yes": "Kyllä",
   "common_no": "Ei",
diff --git a/i18n/messages/fr.json b/i18n/messages/fr.json
index 6f7d66c3..491b1a30 100644
--- a/i18n/messages/fr.json
+++ b/i18n/messages/fr.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "Langue",
   "settings_label_timezone": "Fuseau horaire",
   "settings_label_currency": "Devise",
+  "settings_label_week_start_day": "Premier jour de la semaine",
   "settings_label_unit_distance": "Unité de distance",
   "settings_label_unit_volume": "Unité de volume",
   "settings_label_theme": "Thème",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "Choisissez la langue de l'interface",
   "settings_desc_timezone": "Choisissez votre fuseau horaire pour l'affichage des dates",
   "settings_desc_currency": "Choisissez votre devise préférée",
+  "settings_desc_week_start_day": "Choisissez le premier jour affiché dans les calendriers",
   "settings_desc_unit_distance": "Unité de mesure de distance",
   "settings_desc_unit_volume": "Unité de mesure de volume",
   "settings_label_mileage_format": "Format d'affichage de la consommation",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "Choisissez votre thème préféré",
   "settings_desc_custom_css": "Styles CSS pour personnaliser l'interface",
   "settings_select_language": "Sélectionnez la langue",
+  "settings_select_week_start_day": "Sélectionnez le premier jour",
+  "settings_week_start_language_default": "Par défaut selon la langue",
   "settings_updated_success": "Configuration mise à jour avec succès !",
   "common_example_prefix": "Exemple - ",
   "common_invalid_format": "Format invalide...",
@@ -54,6 +58,13 @@
   "common_mile": "Miles",
   "common_litre": "Litre",
   "common_gallon": "Gallon",
+  "common_sunday": "Dimanche",
+  "common_monday": "Lundi",
+  "common_tuesday": "Mardi",
+  "common_wednesday": "Mercredi",
+  "common_thursday": "Jeudi",
+  "common_friday": "Vendredi",
+  "common_saturday": "Samedi",
   "common_submit": "Envoyer",
   "common_yes": "Oui",
   "common_no": "Non",
diff --git a/i18n/messages/hi.json b/i18n/messages/hi.json
index 4c43115f..c1dbabe6 100644
--- a/i18n/messages/hi.json
+++ b/i18n/messages/hi.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "भाषा",
   "settings_label_timezone": "समय क्षेत्र",
   "settings_label_currency": "मुद्रा",
+  "settings_label_week_start_day": "सप्ताह का पहला दिन",
   "settings_label_unit_distance": "दूरी की इकाई",
   "settings_label_unit_volume": "आयतन की इकाई",
   "settings_label_theme": "थीम",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "इंटरफ़ेस की भाषा चुनें",
   "settings_desc_timezone": "दिनांक प्रदर्शन के लिए अपना समय क्षेत्र चुनें",
   "settings_desc_currency": "अपनी पसंदीदा मुद्रा चुनें",
+  "settings_desc_week_start_day": "कैलेंडर में दिखाया जाने वाला पहला दिन चुनें",
   "settings_desc_unit_distance": "दूरी माप की इकाई",
   "settings_desc_unit_volume": "आयतन माप की इकाई",
   "settings_label_mileage_format": "माइलेज प्रदर्शन प्रारूप",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "अपनी पसंदीदा थीम चुनें",
   "settings_desc_custom_css": "इंटरफ़ेस को कस्टमाइज़ करने के लिए CSS स्टाइल्स",
   "settings_select_language": "भाषा चुनें",
+  "settings_select_week_start_day": "पहला दिन चुनें",
+  "settings_week_start_language_default": "भाषा डिफ़ॉल्ट",
   "settings_updated_success": "कॉन्फ़िगरेशन सफलतापूर्वक अपडेट हुआ!",
   "common_example_prefix": "उदाहरण - ",
   "common_invalid_format": "अमान्य प्रारूप...",
@@ -54,6 +58,13 @@
   "common_mile": "मील",
   "common_litre": "लीटर",
   "common_gallon": "गैलन",
+  "common_sunday": "रविवार",
+  "common_monday": "सोमवार",
+  "common_tuesday": "मंगलवार",
+  "common_wednesday": "बुधवार",
+  "common_thursday": "गुरुवार",
+  "common_friday": "शुक्रवार",
+  "common_saturday": "शनिवार",
   "common_submit": "सबमिट",
   "common_yes": "हाँ",
   "common_no": "नहीं",
diff --git a/i18n/messages/hu.json b/i18n/messages/hu.json
index 71b9df27..26b0f421 100644
--- a/i18n/messages/hu.json
+++ b/i18n/messages/hu.json
@@ -37,6 +37,7 @@
   "settings_label_locale": "Nyelv",
   "settings_label_timezone": "Időzóna",
   "settings_label_currency": "Pénznem",
+  "settings_label_week_start_day": "A hét első napja",
   "settings_label_unit_distance": "Távolság mértékegysége",
   "settings_label_unit_volume": "Térfogat mértékegysége",
   "settings_label_theme": "Téma",
@@ -50,6 +51,7 @@
   "settings_desc_locale": "Válassza ki a felület nyelvét",
   "settings_desc_timezone": "Válassza ki az időzónát a dátumok megjelenítéséhez",
   "settings_desc_currency": "Válassza ki a preferált pénznemet",
+  "settings_desc_week_start_day": "Válaszd ki a naptárakban megjelenő első napot",
   "settings_desc_unit_distance": "A távolság mérésére használt egység",
   "settings_desc_unit_volume": "A térfogat mérésére használt egység",
   "settings_label_mileage_format": "Fogyasztás megjelenítési formátuma",
@@ -61,6 +63,8 @@
   "settings_desc_dark_mode": "Válassza ki a kontraszt stílusát aktív sötét mód esetén",
   "settings_desc_custom_css": "CSS stílusok a felület testreszabásához",
   "settings_select_language": "Nyelv kiválasztása",
+  "settings_select_week_start_day": "Első nap kiválasztása",
+  "settings_week_start_language_default": "Nyelvi alapértelmezés",
   "settings_updated_success": "Konfiguráció sikeresen frissítve!",
   "common_example_prefix": "Példa - ",
   "common_invalid_format": "Érvénytelen formátum...",
@@ -68,6 +72,13 @@
   "common_mile": "Mérföld",
   "common_litre": "Liter",
   "common_gallon": "Gallon",
+  "common_sunday": "Vasárnap",
+  "common_monday": "Hétfő",
+  "common_tuesday": "Kedd",
+  "common_wednesday": "Szerda",
+  "common_thursday": "Csütörtök",
+  "common_friday": "Péntek",
+  "common_saturday": "Szombat",
   "common_submit": "Mentés",
   "common_details": "Részletek",
   "common_close": "Bezárás",
diff --git a/i18n/messages/it.json b/i18n/messages/it.json
index 95d097fc..2d4b6607 100644
--- a/i18n/messages/it.json
+++ b/i18n/messages/it.json
@@ -27,6 +27,7 @@
   "settings_label_locale": "Lingua",
   "settings_label_timezone": "Fuso Orario",
   "settings_label_currency": "Valuta",
+  "settings_label_week_start_day": "Primo giorno della settimana",
   "settings_label_unit_distance": "Unità di Misura Distanza",
   "settings_label_unit_volume": "Unità di Misura Volume",
   "settings_label_theme": "Tema",
@@ -38,6 +39,7 @@
   "settings_desc_locale": "Scegli la lingua per l'interfaccia",
   "settings_desc_timezone": "Scegli il tuo fuso orario per la visualizzazione della data",
   "settings_desc_currency": "Scegli la tua valuta preferita",
+  "settings_desc_week_start_day": "Scegli il primo giorno mostrato nei calendari",
   "settings_desc_unit_distance": "Unità di misura della distanza",
   "settings_desc_unit_volume": "Unità di misura del volume",
   "settings_label_mileage_format": "Formato visualizzazione consumo",
@@ -47,6 +49,8 @@
   "settings_desc_theme": "Scegli il tuo tema preferito",
   "settings_desc_custom_css": "Stili CSS per personalizzare l'interfaccia",
   "settings_select_language": "Seleziona lingua",
+  "settings_select_week_start_day": "Seleziona primo giorno",
+  "settings_week_start_language_default": "Predefinito della lingua",
   "settings_updated_success": "Configurazione aggiornata con successo!",
   "common_example_prefix": "Esempio - ",
   "common_invalid_format": "Formato non valido...",
@@ -54,6 +58,13 @@
   "common_mile": "Miglia",
   "common_litre": "Litro",
   "common_gallon": "Gallone",
+  "common_sunday": "Domenica",
+  "common_monday": "Lunedì",
+  "common_tuesday": "Martedì",
+  "common_wednesday": "Mercoledì",
+  "common_thursday": "Giovedì",
+  "common_friday": "Venerdì",
+  "common_saturday": "Sabato",
   "common_submit": "Invia",
   "common_yes": "Sì",
   "common_no": "No",
diff --git a/i18n/messages/pt-PT.json b/i18n/messages/pt-PT.json
index 676561a0..b6bb4d7b 100644
--- a/i18n/messages/pt-PT.json
+++ b/i18n/messages/pt-PT.json
@@ -37,6 +37,7 @@
   "settings_label_locale": "Idioma",
   "settings_label_timezone": "Fuso horário",
   "settings_label_currency": "Moeda",
+  "settings_label_week_start_day": "Primeiro dia da semana",
   "settings_label_unit_distance": "Unidade de distância",
   "settings_label_unit_volume": "Unidade de combustível",
   "settings_label_theme": "Tema",
@@ -50,6 +51,7 @@
   "settings_desc_locale": "Escolha o idioma da interface",
   "settings_desc_timezone": "Escolha o fuso horário para a apresentação de datas",
   "settings_desc_currency": "Escolha a moeda da sua preferência",
+  "settings_desc_week_start_day": "Escolha o primeiro dia apresentado nos calendários",
   "settings_desc_unit_distance": "Unidade de medida de distância",
   "settings_desc_unit_volume": "Unidade de medida de volume",
   "settings_label_mileage_format": "Formato de apresentação do consumo",
@@ -61,6 +63,8 @@
   "settings_desc_dark_mode": "Escolha o estilo de contraste usado quando o modo escuro está ativo",
   "settings_desc_custom_css": "Estilos CSS para personalizar a interface",
   "settings_select_language": "Selecionar idioma",
+  "settings_select_week_start_day": "Selecionar primeiro dia",
+  "settings_week_start_language_default": "Predefinição do idioma",
   "settings_updated_success": "Definições atualizadas com sucesso!",
   "common_example_prefix": "Exemplo: ",
   "common_invalid_format": "Formato inválido...",
@@ -68,6 +72,13 @@
   "common_mile": "Milha",
   "common_litre": "Litro",
   "common_gallon": "Galão",
+  "common_sunday": "Domingo",
+  "common_monday": "Segunda-feira",
+  "common_tuesday": "Terça-feira",
+  "common_wednesday": "Quarta-feira",
+  "common_thursday": "Quinta-feira",
+  "common_friday": "Sexta-feira",
+  "common_saturday": "Sábado",
   "common_submit": "Submeter",
   "common_details": "Detalhes",
   "common_close": "Fechar",
diff --git a/i18n/messages/ro.json b/i18n/messages/ro.json
index 8b717db2..707a4d18 100644
--- a/i18n/messages/ro.json
+++ b/i18n/messages/ro.json
@@ -28,6 +28,7 @@
   "settings_label_locale": "Limbă / Localizare",
   "settings_label_timezone": "Fus orar",
   "settings_label_currency": "Monedă",
+  "settings_label_week_start_day": "Prima zi a săptămânii",
   "settings_label_unit_distance": "Unitate de distanță",
   "settings_label_unit_volume": "Unitate de combustibil",
   "settings_label_theme": "Temă",
@@ -39,6 +40,7 @@
   "settings_desc_locale": "Alege limba pentru interfață",
   "settings_desc_timezone": "Alege fusul orar pentru afișarea datei",
   "settings_desc_currency": "Alege moneda preferată",
+  "settings_desc_week_start_day": "Alege prima zi afișată în calendare",
   "settings_desc_unit_distance": "Unitatea de măsură pentru distanță",
   "settings_desc_unit_volume": "Unitatea de măsură pentru volum",
   "settings_label_mileage_format": "Format afișare consum",
@@ -49,6 +51,8 @@
   "settings_desc_theme": "Alege tema preferată",
   "settings_desc_custom_css": "Stiluri CSS pentru personalizarea interfeței",
   "settings_select_language": "Selectează limba",
+  "settings_select_week_start_day": "Selectează prima zi",
+  "settings_week_start_language_default": "Implicit pentru limbă",
   "settings_updated_success": "Configurație actualizată cu succes!",
   "common_example_prefix": "Exemplu - ",
   "common_invalid_format": "Format nevalid...",
@@ -56,6 +60,13 @@
   "common_mile": "Mile",
   "common_litre": "Litru",
   "common_gallon": "Galon",
+  "common_sunday": "Duminică",
+  "common_monday": "Luni",
+  "common_tuesday": "Marți",
+  "common_wednesday": "Miercuri",
+  "common_thursday": "Joi",
+  "common_friday": "Vineri",
+  "common_saturday": "Sâmbătă",
   "common_submit": "Trimite",
   "common_yes": "Da",
   "common_no": "Nu",
diff --git a/i18n/messages/ru.json b/i18n/messages/ru.json
index 98436267..67c35da6 100644
--- a/i18n/messages/ru.json
+++ b/i18n/messages/ru.json
@@ -37,6 +37,7 @@
   "settings_label_locale": "Язык",
   "settings_label_timezone": "Часовой пояс",
   "settings_label_currency": "Валюта",
+  "settings_label_week_start_day": "Первый день недели",
   "settings_label_unit_distance": "Единица расстояния",
   "settings_label_unit_volume": "Единица объёма топлива",
   "settings_label_theme": "Тема",
@@ -50,6 +51,7 @@
   "settings_desc_locale": "Выберите язык интерфейса",
   "settings_desc_timezone": "Выберите часовой пояс для отображения дат",
   "settings_desc_currency": "Выберите предпочитаемую валюту",
+  "settings_desc_week_start_day": "Выберите первый день, отображаемый в календарях",
   "settings_desc_unit_distance": "Единица измерения расстояния",
   "settings_desc_unit_volume": "Единица измерения объёма",
   "settings_label_mileage_format": "Формат отображения расхода",
@@ -61,6 +63,8 @@
   "settings_desc_dark_mode": "Выберите контрастность для тёмной темы",
   "settings_desc_custom_css": "CSS-стили для настройки интерфейса",
   "settings_select_language": "Выберите язык",
+  "settings_select_week_start_day": "Выберите первый день",
+  "settings_week_start_language_default": "По умолчанию для языка",
   "settings_updated_success": "Настройки успешно сохранены!",
   "common_example_prefix": "Пример — ",
   "common_invalid_format": "Неверный формат…",
@@ -68,6 +72,13 @@
   "common_mile": "Мили",
   "common_litre": "Литр",
   "common_gallon": "Галлон",
+  "common_sunday": "Воскресенье",
+  "common_monday": "Понедельник",
+  "common_tuesday": "Вторник",
+  "common_wednesday": "Среда",
+  "common_thursday": "Четверг",
+  "common_friday": "Пятница",
+  "common_saturday": "Суббота",
   "common_submit": "Сохранить",
   "common_details": "Подробности",
   "common_close": "Закрыть",
diff --git a/src/__tests__/calendar-week-start.test.ts b/src/__tests__/calendar-week-start.test.ts
new file mode 100644
index 00000000..18ca0a4b
--- /dev/null
+++ b/src/__tests__/calendar-week-start.test.ts
@@ -0,0 +1,65 @@
+import { describe, expect, it } from 'vitest';
+import { resolveWeekStartsOn } from '$lib/helper/date.helper';
+import { createSettingsConfigSchema } from '$lib/helper/settings-form.helper';
+
+const settingsSchema = createSettingsConfigSchema(
+  () => ({ valid: true }),
+  () => true,
+  {
+    includeNotificationProcessingSchedule: true
+  }
+);
+
+describe('calendar week start resolver', () => {
+  it('uses explicit weekday overrides before locale defaults', () => {
+    expect(resolveWeekStartsOn('0', 'cs')).toBe(0);
+    expect(resolveWeekStartsOn('1', 'en')).toBe(1);
+    expect(resolveWeekStartsOn('6', 'de')).toBe(6);
+  });
+
+  it('derives Monday-first calendars from supported European locales', () => {
+    expect(resolveWeekStartsOn('locale', 'cs')).toBe(1);
+    expect(resolveWeekStartsOn('locale', 'de')).toBe(1);
+  });
+
+  it('keeps English language default Sunday-first', () => {
+    expect(resolveWeekStartsOn('locale', 'en')).toBe(0);
+  });
+
+  it('falls back to the locale default for invalid settings', () => {
+    expect(resolveWeekStartsOn('invalid', 'cs')).toBe(1);
+    expect(resolveWeekStartsOn(undefined, 'en')).toBe(0);
+  });
+
+  it('defaults settings to language-based week start', () => {
+    const result = settingsSchema.safeParse({
+      dateFormat: 'dd/MM/yyyy',
+      locale: 'en',
+      timezone: 'UTC',
+      currency: 'USD',
+      unitOfDistance: 'kilometer',
+      unitOfVolume: 'liter',
+      featureFuelLog: true,
+      featureMaintenance: true,
+      featureCompliance: true,
+      featureReminders: true,
+      featureOverview: true,
+      notificationProcessingEnabled: true,
+      notificationProcessingSchedule: '0 9 * * *'
+    });
+
+    expect(result.success).toBe(true);
+    expect(result.data?.weekStartDay).toBe('locale');
+  });
+
+  it('accepts language default and explicit weekday settings', () => {
+    for (const weekStartDay of ['locale', '0', '1', '2', '3', '4', '5', '6']) {
+      expect(settingsSchema.shape.weekStartDay.safeParse(weekStartDay).success).toBe(true);
+    }
+  });
+
+  it('rejects invalid week start settings', () => {
+    expect(settingsSchema.shape.weekStartDay.safeParse('7').success).toBe(false);
+    expect(settingsSchema.shape.weekStartDay.safeParse('monday').success).toBe(false);
+  });
+});
diff --git a/src/lib/components/app/input.svelte b/src/lib/components/app/input.svelte
index aac8f3bc..6319d0a8 100644
--- a/src/lib/components/app/input.svelte
+++ b/src/lib/components/app/input.svelte
@@ -4,8 +4,10 @@
   import type { Component } from 'svelte';
   import * as Popover from '$ui/popover';
   import { Calendar } from '$lib/components/ui/calendar/index.js';
+  import { resolveWeekStartsOn } from '$lib/helper/date.helper';
   import { formatDateForCalendar } from '$lib/helper/format.helper';
   import * as m from '$lib/paraglide/messages';
+  import { configStore } from '$stores/config.svelte';
 
   type InputType = Exclude<HTMLInputTypeAttribute, 'file'> | 'calendar';
 
@@ -27,6 +29,9 @@
   }: Props = $props();
 
   let open = $state(false);
+  const weekStartsOn = $derived(
+    resolveWeekStartsOn(configStore.configs.weekStartDay, configStore.configs.locale)
+  );
 </script>
 
 <div id="input-wrapper" class="relative">
@@ -75,6 +80,7 @@
           id="date-calendar"
           type="single"
           captionLayout="dropdown"
+          {weekStartsOn}
           onValueChange={(v) => {
             if (v) {
               value = formatDateForCalendar(v);
diff --git a/src/lib/components/dashboard/widgets/CalendarWidget.svelte b/src/lib/components/dashboard/widgets/CalendarWidget.svelte
index 8a611bdc..f1191e90 100644
--- a/src/lib/components/dashboard/widgets/CalendarWidget.svelte
+++ b/src/lib/components/dashboard/widgets/CalendarWidget.svelte
@@ -4,7 +4,9 @@
   import { today, getLocalTimeZone, type DateValue } from '@internationalized/date';
   import { getLocale } from '$lib/paraglide/runtime.js';
   import type { DashboardSummary } from '$lib/domain/dashboard';
+  import { resolveWeekStartsOn } from '$lib/helper/date.helper';
   import { formatDateForCalendar } from '$lib/helper/format.helper';
+  import { configStore } from '$stores/config.svelte';
   import Fuel from '@lucide/svelte/icons/fuel';
   import Wrench from '@lucide/svelte/icons/wrench';
   import Bell from '@lucide/svelte/icons/bell';
@@ -63,6 +65,9 @@
   let placeholder = $state<DateValue>(today(getLocalTimeZone()));
 
   const selectedEvents = $derived(eventsByDate.get(selected.toString()) ?? []);
+  const weekStartsOn = $derived(
+    resolveWeekStartsOn(configStore.configs.weekStartDay, configStore.configs.locale)
+  );
 </script>
 
 {#if loading && !summary}
@@ -81,6 +86,7 @@
       weekdayFormat="short"
       monthFormat="long"
       yearFormat="numeric"
+      {weekStartsOn}
       disableDaysOutsideMonth={false}
       locale={getLocale()}
       class="w-full shrink-0 [--cell-size:--spacing(8)]"
diff --git a/src/lib/components/feature/reminder/ReminderCalendar.svelte b/src/lib/components/feature/reminder/ReminderCalendar.svelte
index b3bf3b0a..f01e53e5 100644
--- a/src/lib/components/feature/reminder/ReminderCalendar.svelte
+++ b/src/lib/components/feature/reminder/ReminderCalendar.svelte
@@ -4,6 +4,8 @@
   import { today, getLocalTimeZone, type DateValue } from '@internationalized/date';
   import { getLocale } from '$lib/paraglide/runtime.js';
   import type { Reminder } from '$lib/domain/reminder';
+  import { resolveWeekStartsOn } from '$lib/helper/date.helper';
+  import { configStore } from '$stores/config.svelte';
   import * as m from '$lib/paraglide/messages';
 
   let {
@@ -45,6 +47,9 @@
   let placeholder = $state<DateValue>(today(getLocalTimeZone()));
 
   const reminderKey = (r: Reminder) => r.id ?? `${r.vehicleId}-${r.dueDate.getTime()}`;
+  const weekStartsOn = $derived(
+    resolveWeekStartsOn(configStore.configs.weekStartDay, configStore.configs.locale)
+  );
 </script>
 
 <CalendarPrimitive.Root
@@ -54,6 +59,7 @@
   weekdayFormat="short"
   monthFormat="long"
   yearFormat="numeric"
+  {weekStartsOn}
   disableDaysOutsideMonth={false}
   locale={getLocale()}
   class="w-full [--cell-size:--spacing(9)]"
diff --git a/src/lib/components/feature/settings/SettingsLocalizationFields.svelte b/src/lib/components/feature/settings/SettingsLocalizationFields.svelte
index e0637ef0..b910c9e6 100644
--- a/src/lib/components/feature/settings/SettingsLocalizationFields.svelte
+++ b/src/lib/components/feature/settings/SettingsLocalizationFields.svelte
@@ -6,6 +6,7 @@
   import SettingsSelectField from './SettingsSelectField.svelte';
   import type { SettingsOption } from '$lib/types/settings';
   import Calendar from '@lucide/svelte/icons/calendar';
+  import CalendarDays from '@lucide/svelte/icons/calendar-days';
   import Currency from '@lucide/svelte/icons/currency';
   import Earth from '@lucide/svelte/icons/earth';
   import Languages from '@lucide/svelte/icons/languages';
@@ -16,6 +17,7 @@
     processing: boolean;
     localeOptions: Array<SettingsOption>;
     currencyOptions: Array<SettingsOption>;
+    weekStartDayOptions: Array<SettingsOption>;
     getTimezoneOptions: () => Array<SettingsOption>;
     isValidFormat: (value: string) => { valid: boolean; ex?: string };
     messages: typeof import('$lib/paraglide/messages');
@@ -27,6 +29,7 @@
     processing,
     localeOptions,
     currencyOptions,
+    weekStartDayOptions,
     getTimezoneOptions,
     isValidFormat,
     messages: m
@@ -98,4 +101,15 @@
     </Form.Control>
     <Form.FieldErrors />
   </Form.Field>
+  <SettingsSelectField
+    {form}
+    name="weekStartDay"
+    label={m.settings_label_week_start_day()}
+    description={m.settings_desc_week_start_day()}
+    icon={CalendarDays}
+    options={weekStartDayOptions}
+    placeholder={m.settings_select_week_start_day()}
+    bind:value={$formData.weekStartDay}
+    disabled={processing}
+  />
 </fieldset>
diff --git a/src/lib/helper/date.helper.ts b/src/lib/helper/date.helper.ts
index e8a12b81..c52fc003 100644
--- a/src/lib/helper/date.helper.ts
+++ b/src/lib/helper/date.helper.ts
@@ -15,6 +15,60 @@ export interface FormatConfig {
   mileageUnitFormat: string;
 }
 
+export type WeekStartsOn = 0 | 1 | 2 | 3 | 4 | 5 | 6;
+export type WeekStartDaySetting = 'locale' | `${WeekStartsOn}`;
+
+const WEEK_START_VALUES: Record<string, WeekStartsOn> = {
+  '0': 0,
+  '1': 1,
+  '2': 2,
+  '3': 3,
+  '4': 4,
+  '5': 5,
+  '6': 6
+};
+
+const LOCALE_WEEK_START_FALLBACKS: Record<string, WeekStartsOn> = {
+  ar: 6,
+  cs: 1,
+  de: 1,
+  en: 0,
+  es: 1,
+  fi: 1,
+  fr: 1,
+  hi: 0,
+  hu: 1,
+  it: 1,
+  'pt-PT': 1,
+  ro: 1,
+  ru: 1
+};
+
+const getWeekStartFromIntl = (locale: string): WeekStartsOn | undefined => {
+  try {
+    type LocaleWithWeekInfo = Intl.Locale & { weekInfo?: { firstDay?: number } };
+    const firstDay = (new Intl.Locale(locale) as LocaleWithWeekInfo).weekInfo?.firstDay;
+    if (typeof firstDay !== 'number') return undefined;
+    const weekStartsOn = firstDay % 7;
+    return WEEK_START_VALUES[String(weekStartsOn)];
+  } catch (_) {
+    return undefined;
+  }
+};
+
+export const resolveWeekStartsOn = (setting: unknown, locale: string): WeekStartsOn => {
+  if (typeof setting === 'string' && setting in WEEK_START_VALUES) {
+    return WEEK_START_VALUES[setting];
+  }
+
+  const intlValue = getWeekStartFromIntl(locale);
+  if (intlValue !== undefined) return intlValue;
+
+  return (
+    LOCALE_WEEK_START_FALLBACKS[locale] ?? LOCALE_WEEK_START_FALLBACKS[locale.split('-')[0]] ?? 0
+  );
+};
+
 const getDateFnsLocale = (locale: string) => {
   switch (locale) {
     case 'ar':
diff --git a/src/lib/helper/settings-form.helper.ts b/src/lib/helper/settings-form.helper.ts
index 7c457c39..b6183091 100644
--- a/src/lib/helper/settings-form.helper.ts
+++ b/src/lib/helper/settings-form.helper.ts
@@ -16,6 +16,7 @@ const settingsConfigSchema = z.object({
   mileageUnitFormat: z
     .enum(['distance-per-fuel', 'fuel-per-distance', 'uk-mpg'])
     .default('distance-per-fuel'),
+  weekStartDay: z.enum(['locale', '0', '1', '2', '3', '4', '5', '6']).default('locale'),
   theme: z.string().default('light'),
   darkVariant: z.string().default('default'),
   customCss: z.string().optional(),
@@ -127,6 +128,16 @@ export function createSettingsOptions(
         label: m.settings_mileage_format_uk_mpg()
       }
     ],
+    weekStartDayOptions: [
+      { value: 'locale', label: m.settings_week_start_language_default() },
+      { value: '0', label: m.common_sunday() },
+      { value: '1', label: m.common_monday() },
+      { value: '2', label: m.common_tuesday() },
+      { value: '3', label: m.common_wednesday() },
+      { value: '4', label: m.common_thursday() },
+      { value: '5', label: m.common_friday() },
+      { value: '6', label: m.common_saturday() }
+    ],
     localeOptions: locales.map((code) => ({
       value: code,
       label: localeLabels[code] || code.toUpperCase()
diff --git a/src/lib/stores/config.svelte.ts b/src/lib/stores/config.svelte.ts
index c9a5a57b..3bb8ff55 100644
--- a/src/lib/stores/config.svelte.ts
+++ b/src/lib/stores/config.svelte.ts
@@ -13,6 +13,7 @@ const DEFAULT_CONFIGS: Configs = {
   unitOfLpg: 'liter',
   unitOfCng: 'kilogram',
   mileageUnitFormat: 'distance-per-fuel',
+  weekStartDay: 'locale',
   locale: 'en',
   timezone: 'UTC',
   featureFuelLog: true,
diff --git a/src/routes/(app)/settings/+page.svelte b/src/routes/(app)/settings/+page.svelte
index 11f47771..a0bf3540 100644
--- a/src/routes/(app)/settings/+page.svelte
+++ b/src/routes/(app)/settings/+page.svelte
@@ -118,6 +118,7 @@
     uovOptions,
     gasUnitOptions,
     mileageUnitFormatOptions,
+    weekStartDayOptions,
     localeOptions
   } = createSettingsOptions(m, locales);
 
@@ -309,6 +310,7 @@
               {processing}
               {localeOptions}
               {currencyOptions}
+              {weekStartDayOptions}
               {getTimezoneOptions}
               {isValidFormat}
               messages={m}