Android reminders ring late for two reasons: the app is not allowed to set exact alarms, or a battery saver is holding it back. Allow "Alarms & reminders" for the app, set its battery use to Unrestricted, and on Samsung, Xiaomi and similar phones add it to the maker's own list of apps that may run in the background.
The rest of this post explains what is going on underneath, so you can tell which of the two you are dealing with.
How Android decides when an app may run
A reminder app does not sit awake all day watching the clock. It asks Android to wake it at a set time, and Android decides how strictly to keep that appointment. There are two kinds of request.
- An inexact alarm says "around this time is fine". Android groups these with other apps' wake-ups to save battery, so one can arrive several minutes late, sometimes more.
- An exact alarm says "at this minute". Android keeps it, even when the phone is idle in a drawer.
Calendar and reminder apps need exact alarms. Since Android 12 an app has to be allowed to set them, and on recent versions many apps no longer get that permission automatically when you install them. Without it, the app can only ask for inexact alarms, and that is the classic "my 9:00 reminder showed up at 9:07" problem.
Where the exact alarm setting lives
On a stock Android phone:
- Open Settings.
- Go to Apps, then Special app access.
- Tap Alarms & reminders.
- Pick the reminder app and turn on Allow setting alarms and reminders.
The menu names shift a little between phone makers, but the "Alarms & reminders" page itself is part of Android, so searching for it in the Settings search bar usually finds it.
Doze and battery savers
The second cause is power saving. When the screen is off and the phone is still, Android goes into Doze: background work waits for short maintenance windows instead of running whenever it likes. Exact alarms still get through Doze, which is why the setting above matters so much.
Then Android sorts apps by how often you open them. An app you have not opened for a while gets fewer chances to run in the background, and on recent versions Android can even take back its permissions after a few unused months. A reminder app is the worst case for this: if it works, you rarely need to open it.
Set battery use to Unrestricted
On stock Android and Pixel phones, open Settings > Apps, pick the app, then App battery usage (on some versions just Battery) and choose Unrestricted. On the same app info page, turn off Pause app activity if unused.
Our general Android battery guide walks through these settings and where they sit on different Android versions.
The phone maker's extra layer
Stock Android is only half the story. Samsung, Xiaomi, OPPO, vivo, OnePlus, Huawei and Honor each add their own battery manager on top, with their own lists and switches. These can close an app in the background or stop it starting after a restart, even when Android itself would allow it.
The names differ by brand:
- Samsung (One UI): Battery > Background usage limits, with lists called Sleeping apps, Deep sleeping apps and Never sleeping apps, plus a switch called "Put unused apps to sleep".
- Xiaomi, Redmi and POCO (MIUI, HyperOS): Autostart, and a per-app Battery saver setting with a "No restrictions" option.
- OPPO, realme and OnePlus: "Allow background activity" in the app's battery usage page, and Auto launch.
- vivo: background power consumption management and Autostart.
- Huawei and Honor: App launch, where you switch the app to manual management.
If you have one of these phones, the stock settings are necessary but not enough. The Samsung guide and the Xiaomi, Redmi and POCO guide list each switch in order.
Other things that make reminders late or silent
Cleaner apps and Force stop
Phone cleaners, task killers and "boost" buttons close apps to free memory. Swiping an app out of the recent apps list is fine on most phones. Force stop in the app info page is different: Android treats it as "this app should not run at all", and cancels its pending alarms until you open it again.
A restart
After a restart, an app has to set its alarms again. Android tells apps when the phone has booted, but some battery managers block that message unless the app is allowed to start on its own, which is what Autostart and Auto launch control.
Notifications switched off
Less about timing, more about silence: if notifications are off for the app, or the reminder's notification channel is set to silent, the reminder can arrive on time and still go unnoticed. Check Settings > Apps > the app > Notifications.
How to tell which problem you have
- The reminder appears, but a few minutes late. Exact alarms are probably off. Check Alarms & reminders first.
- It arrives only when you pick up the phone. A battery saver is holding the app back while the screen is off.
- Nothing at all after a restart or a few quiet days. The maker's battery manager, Autostart, or Android pausing an unused app.
- It shows up in the notification shade but made no sound. The notification channel, silent mode or Do Not Disturb. Our post on making a reminder ring on silent covers that side.
How Buzzley handles it
Buzzley asks for notifications and exact alarms when you set it up. After that, a banner on the home screen tells you when something blocks your reminders, and the warnings for notifications switched off and exact alarms denied stay until you fix them. The Alarm not ringing? screen (Settings > Full-screen alarms > Alarm not ringing?) checks notifications, exact alarms, full-screen alarms and battery restrictions, and each Fix button opens the right system page. Under Still not ringing? it shows the steps for your phone's brand, with Open settings buttons for Samsung, Xiaomi, OnePlus, OPPO, vivo, Huawei, Honor, Google, Motorola, ASUS and Nokia. Buzzley also sets its alarms again after a restart, and they ring even while the phone is still locked.
You can try it for 7 days without a card. Plans and prices are on the pricing page.