Why Does My Phone Keep Restarting? 11 Causes and How to Fix It

A phone keeps restarting most often because of a software bug, a bad app, an old or damaged battery, overheating, or very low storage. Sometimes the cause is simple, like a case pressing the power button or a setting that restarts the phone on a schedule.

The good news is that most restart problems can be fixed at home. This guide explains the 11 most common causes and walks you through the fixes on both iPhone and Android, starting with the easiest.

First: how often does it restart?

The pattern gives you a clue about the cause.

11 reasons your phone keeps restarting

1. A scheduled restart or software update

Some phones restart on purpose. Many Samsung phones have a setting that restarts the phone automatically to keep it running well. Phones also restart after installing an update, often overnight.

Fix:

• Samsung: Go to Settings > Device care (or Battery and device care) > Auto optimization and check the Auto restart or Restart when needed settings.
• iPhone: Go to Settings > General > Software Update > Automatic Updates to see if updates install overnight.

If restarts only happen at night and the phone works fine during the day, this is probably the reason.

2. Your software is out of date

Bugs in older software can cause crashes and restarts. Updates often fix them.

Fix:

• iPhone: Go to Settings > General > Software Update.
• Android: Go to Settings > System > Software update (the name may be a little different on your phone).

Also update your apps from the App Store or Google Play Store.

3. A bad app is crashing the phone

A buggy app can crash your phone, especially if it runs in the background. If the restarts started after you installed or updated an app, that app may be the cause.

Fix on Android: use Safe Mode. Safe Mode turns off all the apps you downloaded.

1. Press and hold the power button (or power and volume down) until the power menu appears.
2. Press and hold Power off until you see Safe mode.
3. Tap Safe mode.

If your phone stops restarting in Safe Mode, a downloaded app is the problem. Restart normally, then uninstall recently added or updated apps one at a time until the problem stops.

Fix on iPhone: There is no Safe Mode, so delete apps you installed or updated right before the problem started. Also check Settings > Privacy & Security > Analytics & Improvements > Analytics Data. Many entries that start with "panic" can point to a hardware or system problem. Apple Support can read these logs.

4. Your storage is almost full

When your phone is almost out of space, it has no room for the temporary files it needs to run. Apps may crash, and the phone may restart.

Fix: Check your storage in Settings > General > iPhone Storage or Settings > Storage on Android. Try to keep at least 10% free. Our guide on how to free up space on a full phone shows what to delete first.

5. The battery is old or damaged

A worn battery cannot give the phone steady power. When you open a heavy app, take a photo, or the battery gets low, the phone may suddenly shut off or restart.

How to check:

• iPhone: Go to Settings > Battery > Battery Health (or Battery Health & Charging). A low Maximum Capacity or a service message means the battery may need replacing.
• Android: Many phones show battery health in Settings > Battery or in the maker's support app, like Samsung Members.

Warning signs of a bad battery: the phone dies with charge left, the battery drains very fast, the phone gets hot, or the screen or back looks swollen. If you see swelling, stop using the phone and get it checked right away.

Fix: Replace the battery at the phone maker or a trusted repair shop.

6. The phone is overheating

Phones protect themselves from heat. If your phone gets too hot, it may slow down, dim the screen, or shut off and restart.

Fix: Let it cool down. Take off the case, stop using heavy apps, and move it out of the sun. Never put it in the fridge. Our guide on cooling down an overheating phone explains the common causes.

7. The charger, cable, or charging port is faulty

If restarts happen while charging, the problem may be the power supply. A damaged cable or a cheap charger can send uneven power to the phone.

Fix:

• Try a different cable and wall charger from a trusted brand.
• Look in the charging port with a flashlight. Gently remove lint with a wooden or plastic toothpick.
• Charge on a hard surface, not a bed or couch.

If you have an iPhone that will not charge properly, see our guide on iPhone charging problems.

8. A case or accessory is pressing a button

A tight case, grip, or car mount can press the power button or the power and volume buttons together. On many phones, holding certain buttons forces a restart.

Fix: Take off the case and any accessories for a day and see if the restarts stop.

9. A SIM card problem

A damaged or loose SIM card can sometimes cause restarts or network errors.

Fix: Turn off the phone. Use a SIM tool or paperclip to open the SIM tray, check that the SIM card is clean and sits flat, and put it back. If you use an eSIM, contact your carrier if you see network error messages along with the restarts.

10. A settings problem

Sometimes a mix of settings causes the phone to crash. Resetting settings can help without erasing your photos and apps.

• iPhone: Go to Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings. This resets settings like Wi-Fi passwords and wallpaper, but it does not delete your data.
• Android: Go to Settings > System > Reset options. Choose Reset app preferences or Reset Wi-Fi, mobile & Bluetooth. Do not choose Erase all data unless you have tried everything else.

11. Hardware damage

A drop, water damage, or a failing part inside the phone can cause restarts that no setting can fix. If restarts started after an accident, hardware damage is likely.

Fix: Contact the phone maker or a trusted repair shop. If your phone has a warranty or insurance, the repair may be covered.

What to do if your phone is stuck in a restart loop

A restart loop (or boot loop) is when your phone keeps restarting and never finishes starting up.

1. Force restart the phone.
   • iPhone 8 and newer: Press and quickly let go of volume up, then volume down, then press and hold the side button until you see the Apple logo.
   • Android: Press and hold the power and volume down buttons for about 10 to 20 seconds until the phone restarts.
2. Plug it in to a wall charger for at least 30 minutes. A very low battery can cause a loop.
3. Remove the case and any accessories.
4. Take out the SIM card and try again.
5. Update or restore using a computer.
   • iPhone: Connect to a computer with Finder (Mac) or iTunes or the Apple Devices app (Windows). Put the phone in recovery mode and choose Update. This tries to reinstall iOS without erasing your data.
   • Android: Many phones have a recovery mode with options to wipe the cache or reset. Steps depend on the brand, so check the maker's support website.
6. Get help from the phone maker or a repair shop if the loop continues.

Should you do a factory reset?

A factory reset erases everything and puts the phone back the way it came from the store. It often fixes software problems that cause restarts. But:

• Back up your phone first to iCloud, Google, or a computer.
• Try the other fixes first. A reset should be one of the last steps.
• If the phone still restarts after a reset, the problem is almost certainly hardware.

iPhone vs. Android: what is different?

Most causes are the same on both, but a few tips are specific:

• iPhone: There is no Safe Mode, so finding a bad app takes more trial and error. Battery Health is easy to check in Settings. Apple can read crash logs if you contact support.
• Android: Safe Mode makes it easy to test apps. Some brands, like Samsung, have built-in auto restart settings that can look like a problem but are normal. Battery and device care tools can also show which apps crash most.

How to keep your phone from restarting

• Keep software and apps updated.
• Only install apps from the App Store or Google Play.
• Keep at least 10% of your storage free.
• Use a good charger and cable.
• Keep your phone cool, especially while charging.
• Replace the battery when its health gets low.
• Restart your phone once a week yourself to clear out glitches.

When to get your phone checked

Contact the phone maker or a trusted repair shop if:

• The phone keeps restarting after you tried every step here
• It is stuck in a restart loop
• The battery looks swollen
• The restarts started after a drop or water damage
• It restarts even in Safe Mode (Android) or after a factory reset

The bottom line

A phone that keeps restarting usually has a software bug, a bad app, a worn battery, overheating, or full storage. Start by updating your software and apps, freeing up storage, and removing the case. On Android, use Safe Mode to find a bad app. Check your battery health, and keep the phone cool. If the restarts continue after a reset of settings, or the phone is stuck in a loop, get it checked by the maker or a repair shop.