A phone restarts randomly most often because of a misbehaving app, a software bug that a system update can fix, very low storage, overheating, or an aging battery that cannot hold steady voltage. Water or physical damage can also cause sudden reboots. The goal is to work out whether it is software, which you can usually fix yourself, or hardware, which may need repair.
Why this happens
- A buggy or outdated app crashes and forces the system to reboot, often the same app each time.
- An operating system bug that a pending update is meant to fix.
- Very low free storage, which can make the system unstable.
- Overheating, which triggers a protective restart.
- An old or worn battery whose voltage drops under load, causing sudden shutdowns and reboots.
- Water exposure, a drop, or a loose internal connector after damage.
Is this normal?
No. A healthy phone should stay on until you restart it. Occasional reboots after a big update can happen, but frequent random restarts always have a cause worth fixing.
Does it cause any problems?
Beyond the interruption, random restarts can cause lost unsaved work and, if caused by a failing battery or damage, may get worse over time.
How to fix or check it
- Update the operating system. On iPhone, go to Settings, General, Software Update. On Android, go to Settings, System, Software update.
- Update all apps from the App Store or Google Play, since a bad app is a common cause.
- Free up storage. Delete unused apps, photos, and downloads, and clear space if you are near full.
- Note whether reboots happen while using one specific app, and if so, uninstall or reinstall it.
- On Android, restart into Safe Mode (press and hold power, then long-press Power off and choose Safe mode). If restarts stop, a downloaded app is the cause.
- Check battery health. On iPhone, see Settings, Battery, Battery Health. On Android, check Settings, Battery or Device Care. A worn battery can cause shutdowns.
- Let the phone cool if it is hot, and remove it from any heat source.
- If nothing helps, back up your data and do a factory reset. If restarts continue after a reset, the battery or another part likely needs repair.
Frequently asked questions
How do I know if an app is causing the restarts?
If reboots happen during or right after using one app, that app is likely the cause. On Android, Safe Mode disables downloaded apps to confirm it.
Can a bad battery restart my phone?
Yes. A worn battery can drop voltage under load, especially in cold weather or heavy use, which causes sudden shutdowns and restarts.
Will a factory reset fix random restarts?
It fixes software causes. If the phone still restarts after a clean reset, the problem is almost certainly hardware such as the battery.