The meeting was in your calendar, the time came, and your Android phone stayed silent. Missing calendar reminders on Android almost always come down to a setting rather than a broken app: the event has no notification, the reminder channel is muted, Do Not Disturb is filtering it, or the phone's battery saver put the calendar app to sleep. These fixes work for Google Calendar and Samsung Calendar, and most people are sorted by step five.
The short version: make sure the event has a notification, that your calendar app's event reminder notifications are set to alert with sound, that Do Not Disturb lets Calendar through, and that the app's battery usage is Unrestricted.
Menu names below follow recent Android and Samsung One UI versions; on other brands the same settings may sit under a slightly different name.
1. Check the Event Actually Has a Notification
Open the event and look for the bell icon. In Google Calendar, tap the pencil to edit and check the notification line; in Samsung Calendar, tap Edit and check Alert. If there is none, your phone has nothing to show. Add a reminder such as 15 minutes before, and a second one for anything important. Invitations from other people and events added by other apps often arrive with no reminder.
2. Set Default Notifications for New Events
New events only get a reminder automatically if a default is set.
Google Calendar: tap the menu, then Settings, tap the calendar under your Google account, then Default notifications and All-day notifications. Repeat for each calendar you use.
Samsung Calendar: tap the menu, then the Settings gear, then Default alerts (on some versions, Alert or Notifications) and pick a time for events and all-day events.
Defaults only apply to new events, so existing ones still need step 1.
3. Turn On the Calendar App's Notifications and Reminder Channel
Android lets each app split its notifications into categories, and a calendar app can be allowed to notify while its event reminders category is switched off or set to silent.
Open the app's notification settings. Go to Settings > Apps, choose Calendar (Google) or Samsung Calendar, then Notifications, and make sure notifications are allowed.
Check every category. Open Notification categories (or scroll down the list) and switch on the ones for event reminders and all-day reminders.
Make them alert, not silent. Tap the reminder category, choose Alerting (or Alert), pick a sound and allow pop-ups, so the reminder appears on top of whatever you are doing.
Allow lock screen notifications. In Settings > Notifications > Lock screen, make sure notifications are shown.
Two calendar apps? Samsung phones often have both Google Calendar and Samsung Calendar showing the same Google events. Only the app where you set the reminder will notify you, so pick one app for reminders and check its settings.
4. Check Do Not Disturb and Modes
Do Not Disturb is the most common reason reminders appear in the shade but never make a sound. Open Settings > Notifications > Do Not Disturb (on Samsung, Settings > Modes and Routines or Do not disturb; on newer Android, Settings > Modes). Under Apps or App notifications, add your calendar app as an exception, and check whether Events and reminders are allowed. Look for schedules too: Sleep, Bedtime, Driving or a work routine can switch Do Not Disturb on by itself.
5. Stop Battery Optimisation Putting Calendar to Sleep
This is the classic Android cause of reminders that work for a few days and then stop, especially on Samsung, Xiaomi, OnePlus and Huawei phones.
Set battery usage to Unrestricted. Go to Settings > Apps > [your calendar app] > Battery and choose Unrestricted (not Optimised or Restricted).
Samsung: take it off the sleeping lists. Open Settings > Battery > Background usage limits and make sure the calendar app is not in Sleeping apps or Deep sleeping apps. Add it to Never sleeping apps.
Check Power saving. Strong power-saving modes limit background sync and can delay reminders. Turn it off and see if reminders come back.
6. Allow Alarms and Reminders
On Android 12 and later, apps need the Alarms & reminders permission to fire at an exact time. Go to Settings > Apps > Special app access > Alarms & reminders and make sure your calendar app is allowed. Without it, reminders can arrive several minutes late, which is no use for a call starting now.
7. Make Sure the Calendar Is Syncing
A reminder can only fire for an event your phone actually has. If you add events on a computer, they must sync to the phone before the reminder time.
Turn on account sync. Open Settings > Passwords & accounts (on Samsung, Accounts and backup > Manage accounts), tap your Google account, then Account sync, and make sure Calendar is on. Tap Sync now.
Check the calendar is visible. In the calendar app's menu, make sure the calendar is ticked. Hidden calendars do not notify.
Allow background data. In Settings > Apps > [calendar app] > Mobile data, allow background data, and turn off Data Saver if it is on.
If the problem is with Google Calendar on every device, or with Outlook, see our guides to Google Calendar notifications not working and Outlook calendar notifications not working.
8. The Usual Last Resorts
If everything above looks right, restart the phone, update the calendar app in Google Play or the Galaxy Store, and install any system update. Then clear the calendar app's cache in Settings > Apps > [calendar app] > Storage > Clear cache (not Clear data). Finally, check that Date and time is set automatically, since a wrong time zone makes reminders fire at the wrong time.
Quick Checklist
| Symptom | Most likely cause | Fix |
|---|---|---|
| No reminder for one event | Event has no notification | Edit the event and add one |
| New events never remind | No default notification | Set default notifications |
| No reminders at all | App notifications or reminder category off | Settings > Apps > Calendar > Notifications |
| Reminder in shade but silent | Category set to Silent, or Do Not Disturb | Set category to Alerting, add Calendar as a DND exception |
| Worked, then stopped | Battery optimisation | Battery: Unrestricted, Never sleeping apps |
| Reminders arrive late | Alarms & reminders permission off | Special app access > Alarms & reminders |
| Events from computer missing | Account sync off | Turn on Calendar sync, Sync now |
| Samsung shows events but no alert | Reminder set in the other calendar app | Pick one app and set reminders there |
When a Notification Is Not Enough
Even with every setting right, a calendar reminder is a short sound and a banner. It is easy to miss with your phone in a pocket on vibrate, face down on a desk, or charging in another room. That is the limit of notifications, not a settings problem; we explain why in why calendar notifications fail.
For events you cannot afford to miss, the Remindavo Android app turns each event into a real incoming call that rings until you answer, with a voice that reads the event name: "Client call with Sarah in 10 minutes." It works with the calendars you already use, including Google, Samsung and Outlook, so moved and new events are picked up automatically.
Install Remindavo from Google Play via remindavo.com/mobile-app.
Connect your calendar and pick the calendars you want calls for.
Choose how early you want the call and verify your phone number.
The free plan includes 5 real reminder calls or 14 days, whichever comes first, with no credit card. More on the setup is in our guide to phone call reminders for Android calendar, and for one-off reminders see how to set a reminder on Android. On an iPhone instead? See iPhone calendar notifications not working.