diff --git a/public/i18n.js b/public/i18n.js
index ee3f587..b45a0fe 100644
--- a/public/i18n.js
+++ b/public/i18n.js
@@ -9,7 +9,10 @@ const SUPPORTED_LOCALES = ['de', 'en', 'es', 'fr', 'it', 'sv', 'el', 'ru', 'tr',
 const DEFAULT_LOCALE = 'de';
 const STORAGE_KEY = 'oikos-locale';
 const DATE_FORMAT_KEY = 'oikos-date-format';
+const TIME_FORMAT_KEY = 'oikos-time-format';
 const DEFAULT_DATE_FORMAT = 'dmy';
+const DEFAULT_TIME_FORMAT = '24h';
+const VALID_TIME_FORMATS = ['24h', '12h'];
 
 let currentLocale = DEFAULT_LOCALE;
 let translations = {};
@@ -93,6 +96,15 @@ export function getDateFormat() {
   return getDateFormatPreference();
 }
 
+function getTimeFormatPreference() {
+  const stored = localStorage.getItem(TIME_FORMAT_KEY);
+  return VALID_TIME_FORMATS.includes(stored) ? stored : DEFAULT_TIME_FORMAT;
+}
+
+export function getTimeFormat() {
+  return getTimeFormatPreference();
+}
+
 function formatDateParts(date, useUtc = false) {
   const d = date instanceof Date ? date : new Date(date);
   if (isNaN(d.getTime())) return '';
@@ -176,9 +188,78 @@ export function formatTime(date) {
   if (date == null) return '';
   const d = date instanceof Date ? date : new Date(date);
   if (isNaN(d.getTime())) return '';
+  if (getTimeFormatPreference() === '12h') {
+    const hour = d.getHours();
+    const minute = String(d.getMinutes()).padStart(2, '0');
+    const displayHour = hour % 12 || 12;
+    return `${displayHour}:${minute} ${hour >= 12 ? 'PM' : 'AM'}`;
+  }
   return new Intl.DateTimeFormat(currentLocale, {
     hour: '2-digit',
     minute: '2-digit',
     hour12: false,
   }).format(d);
 }
+
+function toTimeParts(value) {
+  if (value == null || value === '') return null;
+
+  if (value instanceof Date) {
+    if (isNaN(value.getTime())) return null;
+    return { hour: value.getHours(), minute: value.getMinutes() };
+  }
+
+  const raw = String(value).trim();
+  if (!raw) return null;
+
+  if (/^\d{1,2}:\d{2}$/.test(raw)) {
+    const [hour, minute] = raw.split(':').map(Number);
+    if (hour >= 0 && hour < 24 && minute >= 0 && minute < 60) {
+      return { hour, minute };
+    }
+    return null;
+  }
+
+  const ampmMatch = raw.match(/^(\d{1,2})(?::(\d{2}))?\s*([ap]m)$/i);
+  if (ampmMatch) {
+    let hour = Number(ampmMatch[1]);
+    const minute = Number(ampmMatch[2] ?? 0);
+    const meridiem = ampmMatch[3].toLowerCase();
+    if (!Number.isInteger(hour) || !Number.isInteger(minute) || minute < 0 || minute >= 60) return null;
+    if (hour < 1 || hour > 12) return null;
+    if (meridiem === 'pm' && hour !== 12) hour += 12;
+    if (meridiem === 'am' && hour === 12) hour = 0;
+    return { hour, minute };
+  }
+
+  return null;
+}
+
+export function formatTimeInput(value) {
+  const parts = toTimeParts(value);
+  if (!parts) return '';
+  const hour = String(parts.hour).padStart(2, '0');
+  const minute = String(parts.minute).padStart(2, '0');
+  if (getTimeFormatPreference() === '12h') {
+    const isPm = parts.hour >= 12;
+    const displayHour = parts.hour % 12 || 12;
+    return `${displayHour}:${minute} ${isPm ? 'PM' : 'AM'}`;
+  }
+  return `${hour}:${minute}`;
+}
+
+export function parseTimeInput(value) {
+  const raw = String(value || '').trim();
+  if (!raw) return '';
+  const parts = toTimeParts(raw);
+  if (!parts) return '';
+  return `${String(parts.hour).padStart(2, '0')}:${String(parts.minute).padStart(2, '0')}`;
+}
+
+export function isTimeInputValid(value) {
+  return !String(value || '').trim() || !!parseTimeInput(value);
+}
+
+export function timeInputPlaceholder() {
+  return getTimeFormatPreference() === '12h' ? 'h:mm AM/PM' : 'HH:MM';
+}
diff --git a/public/locales/ar.json b/public/locales/ar.json
index 9dc25ef..e247dd4 100644
--- a/public/locales/ar.json
+++ b/public/locales/ar.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "تنسيق التاريخ المفضل",
     "dateFormatHint": "اختر كيف تظهر التواريخ في التطبيق.",
     "dateFormatSavedToast": "تم حفظ تنسيق التاريخ.",
+    "timeFormatLabel": "تنسيق الوقت",
+    "timeFormatHours": "ساعة",
+    "timeFormatSavedToast": "تم حفظ تنسيق الوقت.",
     "themeSystem": "النظام",
     "themeSysLabel": "استخدام إعداد النظام",
     "themeLight": "فاتح",
diff --git a/public/locales/de.json b/public/locales/de.json
index 09be1e2..aec8962 100644
--- a/public/locales/de.json
+++ b/public/locales/de.json
@@ -632,6 +632,9 @@
     "dateFormatLabel": "Bevorzugtes Datumsformat",
     "dateFormatHint": "Wähle, wie Daten in der App angezeigt werden.",
     "dateFormatSavedToast": "Datumsformat gespeichert.",
+    "timeFormatLabel": "Zeitformat",
+    "timeFormatHours": "Stunden",
+    "timeFormatSavedToast": "Zeitformat gespeichert.",
     "themeSystem": "System",
     "themeSysLabel": "System-Einstellung verwenden",
     "themeLight": "Hell",
diff --git a/public/locales/el.json b/public/locales/el.json
index 3cd0e17..e3230bb 100644
--- a/public/locales/el.json
+++ b/public/locales/el.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Προτιμώμενη μορφή ημερομηνίας",
     "dateFormatHint": "Επιλέξτε πώς εμφανίζονται οι ημερομηνίες στην εφαρμογή.",
     "dateFormatSavedToast": "Η μορφή ημερομηνίας αποθηκεύτηκε.",
+    "timeFormatLabel": "Μορφή ώρας",
+    "timeFormatHours": "ώρες",
+    "timeFormatSavedToast": "Η μορφή ώρας αποθηκεύτηκε.",
     "themeSystem": "Σύστημα",
     "themeSysLabel": "Χρήση ρύθμισης συστήματος",
     "themeLight": "Ανοιχτό",
diff --git a/public/locales/en.json b/public/locales/en.json
index b9d3157..21462d9 100644
--- a/public/locales/en.json
+++ b/public/locales/en.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Preferred date format",
     "dateFormatHint": "Choose how dates are displayed throughout the app.",
     "dateFormatSavedToast": "Date format saved.",
+    "timeFormatLabel": "Time format",
+    "timeFormatHours": "hours",
+    "timeFormatSavedToast": "Time format saved.",
     "themeSystem": "System",
     "themeSysLabel": "Use system setting",
     "themeLight": "Light",
@@ -1019,4 +1022,4 @@
     "dropzoneHint": "Drag a file into this area, or use the file picker.",
     "selectedFileLabel": "Selected: {{name}}"
   }
-}
\ No newline at end of file
+}
diff --git a/public/locales/es.json b/public/locales/es.json
index 5410d31..6c4ca09 100644
--- a/public/locales/es.json
+++ b/public/locales/es.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Formato de fecha preferido",
     "dateFormatHint": "Elige cómo se muestran las fechas en toda la app.",
     "dateFormatSavedToast": "Formato de fecha guardado.",
+    "timeFormatLabel": "Formato de hora",
+    "timeFormatHours": "horas",
+    "timeFormatSavedToast": "Formato de hora guardado.",
     "themeSystem": "Sistema",
     "themeSysLabel": "Usar configuración del sistema",
     "themeLight": "Claro",
diff --git a/public/locales/fr.json b/public/locales/fr.json
index 9641f44..d804651 100644
--- a/public/locales/fr.json
+++ b/public/locales/fr.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Format de date préféré",
     "dateFormatHint": "Choisissez comment les dates sont affichées dans l'application.",
     "dateFormatSavedToast": "Format de date enregistré.",
+    "timeFormatLabel": "Format de l'heure",
+    "timeFormatHours": "heures",
+    "timeFormatSavedToast": "Format de l'heure enregistré.",
     "themeSystem": "Système",
     "themeSysLabel": "Utiliser le paramètre système",
     "themeLight": "Clair",
diff --git a/public/locales/hi.json b/public/locales/hi.json
index e64aa80..028f1a1 100644
--- a/public/locales/hi.json
+++ b/public/locales/hi.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "पसंदीदा तारीख प्रारूप",
     "dateFormatHint": "चुनें कि ऐप में तारीखें कैसे दिखाई दें।",
     "dateFormatSavedToast": "तारीख प्रारूप सहेजा गया।",
+    "timeFormatLabel": "समय प्रारूप",
+    "timeFormatHours": "घंटे",
+    "timeFormatSavedToast": "समय प्रारूप सहेजा गया।",
     "themeSystem": "सिस्टम",
     "themeSysLabel": "सिस्टम सेटिंग का उपयोग करें",
     "themeLight": "हल्का",
diff --git a/public/locales/it.json b/public/locales/it.json
index 4bb0782..f8dceed 100644
--- a/public/locales/it.json
+++ b/public/locales/it.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Formato data preferito",
     "dateFormatHint": "Scegli come vengono mostrate le date nell'app.",
     "dateFormatSavedToast": "Formato data salvato.",
+    "timeFormatLabel": "Formato orario",
+    "timeFormatHours": "ore",
+    "timeFormatSavedToast": "Formato orario salvato.",
     "themeSystem": "Sistema",
     "themeSysLabel": "Usa impostazione di sistema",
     "themeLight": "Chiaro",
diff --git a/public/locales/ja.json b/public/locales/ja.json
index 2dc64a4..fa047db 100644
--- a/public/locales/ja.json
+++ b/public/locales/ja.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "希望する日付形式",
     "dateFormatHint": "アプリ内で日付をどう表示するかを選択します。",
     "dateFormatSavedToast": "日付形式を保存しました。",
+    "timeFormatLabel": "時刻形式",
+    "timeFormatHours": "時間",
+    "timeFormatSavedToast": "時刻形式を保存しました。",
     "themeSystem": "システム設定",
     "themeSysLabel": "システム設定を使用",
     "themeLight": "ライト",
diff --git a/public/locales/pt.json b/public/locales/pt.json
index 612b633..32b1e7f 100644
--- a/public/locales/pt.json
+++ b/public/locales/pt.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Formato preferido da data",
     "dateFormatHint": "Escolha como as datas aparecem em toda a aplicação.",
     "dateFormatSavedToast": "Formato da data salvo.",
+    "timeFormatLabel": "Formato de hora",
+    "timeFormatHours": "horas",
+    "timeFormatSavedToast": "Formato de hora salvo.",
     "themeSystem": "Sistema",
     "themeSysLabel": "Usar configuração do sistema",
     "themeLight": "Claro",
diff --git a/public/locales/ru.json b/public/locales/ru.json
index 60e5983..8de0150 100644
--- a/public/locales/ru.json
+++ b/public/locales/ru.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Предпочитаемый формат даты",
     "dateFormatHint": "Выберите, как даты отображаются в приложении.",
     "dateFormatSavedToast": "Формат даты сохранён.",
+    "timeFormatLabel": "Формат времени",
+    "timeFormatHours": "часов",
+    "timeFormatSavedToast": "Формат времени сохранён.",
     "themeSystem": "Система",
     "themeSysLabel": "Использовать системную настройку",
     "themeLight": "Светлая",
diff --git a/public/locales/sv.json b/public/locales/sv.json
index 27b17e5..37a2198 100644
--- a/public/locales/sv.json
+++ b/public/locales/sv.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Önskat datumformat",
     "dateFormatHint": "Välj hur datum visas i appen.",
     "dateFormatSavedToast": "Datumformat sparat.",
+    "timeFormatLabel": "Tidsformat",
+    "timeFormatHours": "timmar",
+    "timeFormatSavedToast": "Tidsformat sparat.",
     "themeSystem": "System",
     "themeSysLabel": "Använd systeminställning",
     "themeLight": "Ljus",
diff --git a/public/locales/tr.json b/public/locales/tr.json
index 8cda108..e0e9dbd 100644
--- a/public/locales/tr.json
+++ b/public/locales/tr.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Tercih edilen tarih biçimi",
     "dateFormatHint": "Tarihlerin uygulamada nasıl görüneceğini seçin.",
     "dateFormatSavedToast": "Tarih biçimi kaydedildi.",
+    "timeFormatLabel": "Saat biçimi",
+    "timeFormatHours": "saat",
+    "timeFormatSavedToast": "Saat biçimi kaydedildi.",
     "themeSystem": "Sistem",
     "themeSysLabel": "Sistem ayarını kullan",
     "themeLight": "Açık",
diff --git a/public/locales/uk.json b/public/locales/uk.json
index 272cde9..7d97282 100644
--- a/public/locales/uk.json
+++ b/public/locales/uk.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "Бажаний формат дати",
     "dateFormatHint": "Виберіть, як дати відображаються в застосунку.",
     "dateFormatSavedToast": "Формат дати збережено.",
+    "timeFormatLabel": "Формат часу",
+    "timeFormatHours": "годин",
+    "timeFormatSavedToast": "Формат часу збережено.",
     "themeSystem": "Системна",
     "themeSysLabel": "Використовувати системні налаштування",
     "themeLight": "Світла",
diff --git a/public/locales/zh.json b/public/locales/zh.json
index e0ef6e8..babffb6 100644
--- a/public/locales/zh.json
+++ b/public/locales/zh.json
@@ -607,6 +607,9 @@
     "dateFormatLabel": "首选日期格式",
     "dateFormatHint": "选择日期在应用中的显示方式。",
     "dateFormatSavedToast": "日期格式已保存。",
+    "timeFormatLabel": "时间格式",
+    "timeFormatHours": "小时",
+    "timeFormatSavedToast": "时间格式已保存。",
     "themeSystem": "跟随系统",
     "themeSysLabel": "使用系统设置",
     "themeLight": "浅色",
diff --git a/public/pages/calendar.js b/public/pages/calendar.js
index 1553d7e..d5cb96a 100644
--- a/public/pages/calendar.js
+++ b/public/pages/calendar.js
@@ -8,7 +8,7 @@ import { api } from '/api.js';
 import { renderRRuleFields, bindRRuleEvents, getRRuleValues } from '/rrule-ui.js';
 import { openModal as openSharedModal, closeModal } from '/components/modal.js';
 import { stagger } from '/utils/ux.js';
-import { t, formatDate as formatPreferredDate, formatTime, dateInputPlaceholder, formatDateInput, parseDateInput, isDateInputValid } from '/i18n.js';
+import { t, formatDate as formatPreferredDate, formatTime, dateInputPlaceholder, formatDateInput, parseDateInput, isDateInputValid, formatTimeInput, parseTimeInput, timeInputPlaceholder } from '/i18n.js';
 import { esc, fmtLocation } from '/utils/html.js';
 import { refresh as refreshReminders } from '/reminders.js';
 
@@ -171,6 +171,7 @@ const EVENT_ICONS = [
 const CUSTOM_EVENT_ICONS = new Set(['tooth']);
 const MAX_ATTACHMENT_BYTES = 5 * 1024 * 1024;
 const ATTACHMENT_IMAGE_MIME = new Set(['image/png', 'image/jpeg', 'image/webp', 'image/gif']);
+const CALENDAR_VIEW_STORAGE_KEY = 'oikos-calendar-view';
 
 const HOUR_HEIGHT = 56; // px pro Stunde in Wochen-/Tagesansicht
 
@@ -212,6 +213,22 @@ let _container = null;
 function pad(n) { return String(n).padStart(2, '0'); }
 function isoDate(d) { return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}`; }
 
+function getSavedCalendarView() {
+  try {
+    const saved = localStorage.getItem(CALENDAR_VIEW_STORAGE_KEY);
+    return VIEWS.includes(saved) ? saved : 'month';
+  } catch {
+    return 'month';
+  }
+}
+
+function setSavedCalendarView(view) {
+  if (!VIEWS.includes(view)) return;
+  try {
+    localStorage.setItem(CALENDAR_VIEW_STORAGE_KEY, view);
+  } catch {}
+}
+
 // Extract YYYY-MM-DD in the browser's local timezone from any datetime string.
 // For date-only strings (≤10 chars) slicing is safe; for datetime strings with an
 // explicit UTC offset or 'Z' suffix, new Date() converts to local before extraction.
@@ -438,7 +455,7 @@ export async function render(container, { user }) {
   _container = container;
   state.today  = isoDate(new Date());
   state.cursor = state.today;
-  state.view   = 'month';
+  state.view   = getSavedCalendarView();
 
   container.innerHTML = `
     <div class="calendar-page" id="calendar-page">
@@ -506,6 +523,7 @@ function renderToolbar() {
     btn.addEventListener('click', async () => {
       if (btn.dataset.view === state.view) return;
       state.view = btn.dataset.view;
+      setSavedCalendarView(state.view);
       bar.querySelectorAll('[data-view]').forEach((b) =>
         b.classList.toggle('cal-toolbar__view-btn--active', b.dataset.view === state.view)
       );
@@ -1184,6 +1202,15 @@ function renderCalendarReminderSection(reminder = null, event = null) {
     </div>`;
 }
 
+function bindTimeInputs(root) {
+  root.querySelectorAll('.js-time-input').forEach((input) => {
+    input.addEventListener('blur', () => {
+      const parsed = parseTimeInput(input.value);
+      if (parsed) input.value = formatTimeInput(parsed);
+    });
+  });
+}
+
 // --------------------------------------------------------
 // Event-Modal (Erstellen / Bearbeiten)
 // --------------------------------------------------------
@@ -1245,6 +1272,7 @@ function openEventModal({ mode, event = null, date = null, reminder = null }) {
       if (isEdit && event?.all_day) { timeFields.style.display = 'none'; alldayFields.style.display = ''; }
 
       bindDateInputs(panel);
+      bindTimeInputs(panel);
 
       const iconInput = panel.querySelector('#modal-icon');
       const iconTrigger = panel.querySelector('#modal-icon-trigger');
@@ -1435,7 +1463,7 @@ function buildEventModalContent({ mode, event, date, reminder = null }) {
         </div>
         <div class="form-group">
           <label class="form-label" for="modal-start-time">${t('calendar.startTimeLabel')}</label>
-          <input type="time" class="form-input" id="modal-start-time" value="${startTime}">
+          <input type="text" class="form-input js-time-input" id="modal-start-time" value="${formatTimeInput(startTime)}" placeholder="${timeInputPlaceholder()}">
         </div>
       </div>
       <div class="modal-grid modal-grid--2">
@@ -1445,7 +1473,7 @@ function buildEventModalContent({ mode, event, date, reminder = null }) {
         </div>
         <div class="form-group">
           <label class="form-label" for="modal-end-time">${t('calendar.endTimeLabel')}</label>
-          <input type="time" class="form-input" id="modal-end-time" value="${endTime}">
+          <input type="text" class="form-input js-time-input" id="modal-end-time" value="${formatTimeInput(endTime)}" placeholder="${timeInputPlaceholder()}">
         </div>
       </div>
     </div>
@@ -1553,9 +1581,15 @@ async function saveEvent(overlay, mode, eventId, existingReminder = null, attach
     end_datetime   = end_datetime || null;
   } else {
     const sd = readDateInput(overlay, '#modal-start-date');
-    const st = overlay.querySelector('#modal-start-time').value;
+    const stRaw = overlay.querySelector('#modal-start-time').value;
+    const st = parseTimeInput(stRaw);
     const ed = readDateInput(overlay, '#modal-end-date');
-    const et = overlay.querySelector('#modal-end-time').value;
+    const etRaw = overlay.querySelector('#modal-end-time').value;
+    const et = parseTimeInput(etRaw);
+    if ((stRaw && !st) || (etRaw && !et)) {
+      window.oikos?.showToast(t('calendar.invalidDate'), 'error');
+      return;
+    }
     start_datetime = st ? `${sd}T${st}` : sd;
     end_datetime   = ed ? (et ? `${ed}T${et}` : ed) : null;
   }
diff --git a/public/pages/settings.js b/public/pages/settings.js
index 6ca6a29..6f195cd 100644
--- a/public/pages/settings.js
+++ b/public/pages/settings.js
@@ -199,7 +199,7 @@ export async function render(container, { user }) {
   let users           = [];
   let googleStatus    = { configured: false, connected: false, lastSync: null };
   let appleStatus     = { configured: false, lastSync: null };
-  let prefs           = { visible_meal_types: ['breakfast', 'lunch', 'dinner', 'snack'], currency: 'EUR', date_format: 'mdy', app_name: DEFAULT_APP_NAME };
+  let prefs           = { visible_meal_types: ['breakfast', 'lunch', 'dinner', 'snack'], currency: 'EUR', date_format: 'mdy', time_format: '24h', app_name: DEFAULT_APP_NAME };
   let categories      = [];
   let icsSubscriptions = [];
   let apiTokens       = [];
@@ -226,6 +226,9 @@ export async function render(container, { user }) {
   if (prefs.date_format) {
     try { localStorage.setItem('oikos-date-format', prefs.date_format); } catch (_) {}
   }
+  if (prefs.time_format) {
+    try { localStorage.setItem('oikos-time-format', prefs.time_format); } catch (_) {}
+  }
   if (prefs.app_name) {
     try { localStorage.setItem(APP_NAME_STORAGE_KEY, prefs.app_name); } catch (_) {}
   }
@@ -338,6 +341,11 @@ export async function render(container, { user }) {
               <option value="dmy"${prefs.date_format === 'dmy' ? ' selected' : ''}>DD/MM/YYYY</option>
               <option value="ymd"${prefs.date_format === 'ymd' ? ' selected' : ''}>YYYY-MM-DD</option>
             </select>
+            <label class="form-label" for="time-format-select" style="margin-top:var(--space-3)">${t('settings.timeFormatLabel')}</label>
+            <select class="form-input" id="time-format-select">
+              <option value="24h"${prefs.time_format === '24h' ? ' selected' : ''}>24 ${t('settings.timeFormatHours')}</option>
+              <option value="12h"${prefs.time_format === '12h' ? ' selected' : ''}>AM/PM</option>
+            </select>
           </div>
         </section>
 
@@ -858,6 +866,20 @@ function bindEvents(container, user, users, categories, icsSubscriptions, apiTok
     });
   }
 
+  const timeFormatSelect = container.querySelector('#time-format-select');
+  if (timeFormatSelect) {
+    timeFormatSelect.addEventListener('change', async () => {
+      try {
+        await api.put('/preferences', { time_format: timeFormatSelect.value });
+        try { localStorage.setItem('oikos-time-format', timeFormatSelect.value); } catch (_) {}
+        window.dispatchEvent(new CustomEvent('time-format-changed', { detail: { timeFormat: timeFormatSelect.value } }));
+        window.oikos?.showToast(t('settings.timeFormatSavedToast'), 'success');
+      } catch (err) {
+        window.oikos?.showToast(err.message ?? t('common.errorGeneric'), 'danger');
+      }
+    });
+  }
+
   const appNameForm = container.querySelector('#app-name-form');
   if (appNameForm) {
     appNameForm.addEventListener('submit', async (e) => {
diff --git a/public/pages/tasks.js b/public/pages/tasks.js
index f6e09ff..9b2cc06 100644
--- a/public/pages/tasks.js
+++ b/public/pages/tasks.js
@@ -8,7 +8,7 @@ import { api } from '/api.js';
 import { renderRRuleFields, bindRRuleEvents, getRRuleValues } from '/rrule-ui.js';
 import { openModal as openSharedModal, closeModal, wireBlurValidation, validateAll, btnSuccess, btnError, promptModal } from '/components/modal.js';
 import { stagger, vibrate } from '/utils/ux.js';
-import { t, formatDate, formatTime, dateInputPlaceholder, formatDateInput, parseDateInput, isDateInputValid } from '/i18n.js';
+import { t, formatDate, formatTime, dateInputPlaceholder, formatDateInput, parseDateInput, isDateInputValid, formatTimeInput, parseTimeInput, timeInputPlaceholder } from '/i18n.js';
 import { esc } from '/utils/html.js';
 import { refresh as refreshReminders } from '/reminders.js';
 
@@ -361,8 +361,8 @@ function renderModalContent({ task = null, users = [], reminder = null } = {}) {
         </div>
         <div class="form-group">
           <label class="label" for="task-due-time">${t('tasks.dueTimeLabel')}</label>
-          <input class="input" type="time" id="task-due-time" name="due_time"
-                 value="${task?.due_time ?? ''}">
+          <input class="input js-time-input" type="text" id="task-due-time" name="due_time"
+                 value="${formatTimeInput(task?.due_time ?? '')}" placeholder="${timeInputPlaceholder()}">
         </div>
       </div>
 
@@ -566,6 +566,12 @@ function openTaskModal({ task = null, users = [], reminder = null } = {}, contai
           if (parsed) input.value = formatDateInput(parsed);
         });
       });
+      panel.querySelectorAll('.js-time-input').forEach((input) => {
+        input.addEventListener('blur', () => {
+          const parsed = parseTimeInput(input.value);
+          if (parsed) input.value = formatTimeInput(parsed);
+        });
+      });
 
       // Form-Events
       panel.querySelector('#task-form')
@@ -614,11 +620,20 @@ async function handleFormSubmit(e, container) {
     priority:        form.priority.value,
     category:        form.category.value,
     due_date:        dueDate || null,
-    due_time:        form.due_time?.value || null,
     assigned_to:     form.assigned_to.value ? Number(form.assigned_to.value) : null,
     is_recurring:    rrule.is_recurring ? 1 : 0,
     recurrence_rule: rrule.recurrence_rule,
   };
+  const dueTimeRaw = form.due_time?.value || '';
+  const dueTime = parseTimeInput(dueTimeRaw);
+  if (dueTimeRaw && !dueTime) {
+    errorEl.textContent = t('calendar.invalidDate');
+    errorEl.hidden = false;
+    submitBtn.disabled = false;
+    submitBtn.textContent = originalLabel;
+    return;
+  }
+  body.due_time = dueTime || null;
   if (form.status) body.status = form.status.value;
 
   try {
diff --git a/public/router.js b/public/router.js
index 62c4adc..0105c59 100644
--- a/public/router.js
+++ b/public/router.js
@@ -300,6 +300,10 @@ async function syncPreferencesOnce() {
     if (dateFormat) {
       localStorage.setItem('oikos-date-format', dateFormat);
     }
+    const timeFormat = res?.data?.time_format;
+    if (timeFormat) {
+      localStorage.setItem('oikos-time-format', timeFormat);
+    }
     if (res?.data?.app_name) {
       setAppName(res.data.app_name);
       updateBranding();
@@ -1332,6 +1336,17 @@ window.addEventListener('app-name-changed', () => {
   updateBranding(currentPath || '/');
 });
 
+function refreshCurrentRoute() {
+  if (!currentPath) return;
+  setTimeout(() => {
+    if (!currentPath) return;
+    navigate(currentPath, false);
+  }, 0);
+}
+
+window.addEventListener('date-format-changed', refreshCurrentRoute);
+window.addEventListener('time-format-changed', refreshCurrentRoute);
+
 // --------------------------------------------------------
 // Virtuelle Tastatur: FAB ausblenden wenn Keyboard offen
 // Erkennung via visualViewport - Höhe < 75% des Fensters = Keyboard aktiv.
diff --git a/server/routes/preferences.js b/server/routes/preferences.js
index d02888d..ce81401 100644
--- a/server/routes/preferences.js
+++ b/server/routes/preferences.js
@@ -22,6 +22,8 @@ const DEFAULT_APP_NAME = 'Oikos';
 
 const VALID_DATE_FORMATS = ['mdy', 'dmy', 'ymd'];
 const DEFAULT_DATE_FORMAT = 'mdy';
+const VALID_TIME_FORMATS = ['24h', '12h'];
+const DEFAULT_TIME_FORMAT = '24h';
 
 const VALID_WIDGET_IDS = ['tasks', 'calendar', 'birthdays', 'budget', 'family', 'weather', 'shopping', 'meals', 'notes'];
 const DEFAULT_WIDGET_CONFIG = JSON.stringify(VALID_WIDGET_IDS.map((id) => ({ id, visible: true })));
@@ -88,6 +90,7 @@ router.get('/', (req, res) => {
     const visibleMealTypes = raw.split(',').filter((t) => VALID_MEAL_TYPES.includes(t));
     const currency = cfgGet('currency') ?? DEFAULT_CURRENCY;
     const dateFormat = VALID_DATE_FORMATS.includes(cfgGet('date_format')) ? cfgGet('date_format') : DEFAULT_DATE_FORMAT;
+    const timeFormat = VALID_TIME_FORMATS.includes(cfgGet('time_format')) ? cfgGet('time_format') : DEFAULT_TIME_FORMAT;
     const appName = cfgGet('app_name') ?? DEFAULT_APP_NAME;
     const dashboardWidgets = parseWidgetConfig(cfgGet('dashboard_widgets'));
 
@@ -96,6 +99,7 @@ router.get('/', (req, res) => {
         visible_meal_types: visibleMealTypes,
         currency,
         date_format: dateFormat,
+        time_format: timeFormat,
         app_name: appName,
         dashboard_widgets: dashboardWidgets,
       },
@@ -115,7 +119,7 @@ router.get('/', (req, res) => {
 
 router.put('/', (req, res) => {
   try {
-    const { visible_meal_types, currency, date_format, app_name, dashboard_widgets } = req.body;
+    const { visible_meal_types, currency, date_format, time_format, app_name, dashboard_widgets } = req.body;
 
     if (visible_meal_types !== undefined) {
       if (!Array.isArray(visible_meal_types)) {
@@ -142,6 +146,13 @@ router.put('/', (req, res) => {
       cfgSet('date_format', date_format);
     }
 
+    if (time_format !== undefined) {
+      if (!VALID_TIME_FORMATS.includes(time_format)) {
+        return res.status(400).json({ error: `Invalid time format. Allowed: ${VALID_TIME_FORMATS.join(', ')}`, code: 400 });
+      }
+      cfgSet('time_format', time_format);
+    }
+
     if (app_name !== undefined) {
       const vAppName = str(app_name, 'Application name', { max: MAX_SHORT, required: false });
       if (vAppName.error) return res.status(400).json({ error: vAppName.error, code: 400 });
@@ -161,6 +172,7 @@ router.put('/', (req, res) => {
     const savedMealTypes = rawMealTypes.split(',').filter((t) => VALID_MEAL_TYPES.includes(t));
     const savedCurrency = cfgGet('currency') ?? DEFAULT_CURRENCY;
     const savedDateFormat = VALID_DATE_FORMATS.includes(cfgGet('date_format')) ? cfgGet('date_format') : DEFAULT_DATE_FORMAT;
+    const savedTimeFormat = VALID_TIME_FORMATS.includes(cfgGet('time_format')) ? cfgGet('time_format') : DEFAULT_TIME_FORMAT;
     const savedAppName = cfgGet('app_name') ?? DEFAULT_APP_NAME;
     const savedWidgets = parseWidgetConfig(cfgGet('dashboard_widgets'));
 
@@ -169,6 +181,7 @@ router.put('/', (req, res) => {
         visible_meal_types: savedMealTypes,
         currency: savedCurrency,
         date_format: savedDateFormat,
+        time_format: savedTimeFormat,
         app_name: savedAppName,
         dashboard_widgets: savedWidgets,
       },