Quick answer
If your iPhone keeps restarting, first disconnect accessories, let the phone cool if it is hot, check available storage, install iOS and app updates, and note whether the restart happens during one specific task. If the phone is stuck in a restart loop, use a force restart appropriate for your model. Back up important data as soon as the phone stays on long enough. Repeated restarts after a drop, liquid exposure, battery swelling, or extreme heat need professional diagnosis.
Common causes
- Very low storage or a software process that repeatedly crashes.
- An incomplete update or problematic app.
- Battery, charging, temperature, or accessory problems.
- Physical or liquid damage.
Safe fixes to try
1. Disconnect accessories and charging equipment
Remove cables, adapters and connected accessories, then test the iPhone by itself. If restarts happen only with one accessory, stop using that accessory until it is checked.
2. Check temperature
If the phone is unusually hot, stop charging and intensive use and allow it to cool naturally in a dry, shaded place. Do not use ice, water, a refrigerator or freezer.
3. Force restart only when necessary
If the screen is frozen or the phone is looping, use Apple’s force-restart procedure for your iPhone model. A force restart does not normally erase personal data, but it should not be repeated continuously as a substitute for diagnosing the cause.
4. Check storage
When the phone remains on, open Settings > General > iPhone Storage. If space is critically low, remove unnecessary downloads or apps carefully. See our iPhone storage full guide for safer cleanup steps.
5. Update iOS and apps
Install available trusted updates while the phone has stable power and enough storage. If the problem began immediately after an update, allow normal background setup to finish before making disruptive changes.
6. Identify a repeatable trigger
Notice whether restarts happen during charging, camera use, gaming, cellular use or one app. A repeatable trigger helps separate an app or workload issue from a broader hardware problem.
7. Back up before advanced recovery
If restarts continue but the phone stays usable, create a current backup before considering reset or computer-based recovery options. Do not erase the phone until you understand what data and account credentials will be required afterward.
Before you start: protect your data
A restart problem can change from occasional to constant without warning. If the iPhone stays on long enough, make a current backup before advanced troubleshooting. Keep the phone connected to a stable network and reliable power only if charging does not appear to trigger the problem.
Advanced checks
Review battery condition and restart patterns
Check the battery information available in Settings and pay attention to whether the phone shuts down at a particular charge level or only under heavy load. Battery information is a clue, not a complete hardware diagnosis. Avoid replacing parts solely because a percentage or status looks unusual.
Separate app problems from system-wide problems
If the restart consistently follows one app, update that app and iOS, then test again. If necessary, remove the suspected app only after confirming that any locally stored app data you need is backed up or synchronized. If the phone restarts even when idle and with no accessories attached, the cause is less likely to be one foreground app.
Use recovery options carefully
If the iPhone cannot start normally after basic checks, Apple provides computer-based recovery options. These are advanced steps because some recovery choices can reinstall software or erase data. Read the on-screen choice carefully, use a trusted computer and cable, and preserve a backup whenever possible.
Quick diagnostic checklist
- Does it restart only while charging?
- Does it restart only when the phone is hot?
- Did the issue begin after a new app, update, drop or liquid exposure?
- Is storage critically low?
- Can the phone remain on long enough to complete a backup?
Writing down these answers makes a repair consultation more useful and reduces unnecessary resets or part replacements.
What not to do
- Do not repeatedly factory-reset without a backup.
- Do not open a swollen, hot or liquid-damaged iPhone.
- Do not install “repair” or “cleaner” apps that promise to fix hardware faults.
When professional repair is needed
Seek qualified service when restarts continue after software and storage checks, or when the problem follows a drop, liquid exposure, severe overheating or charging damage. Stop using the device immediately if the battery swells, the enclosure separates, or you notice smoke, hissing, leaking or a chemical/burning smell.
Related guides
If heat accompanies the restarts, use our iPhone overheating guide. If power is unstable, also check iPhone not charging fixes.
FAQ
Will a force restart delete my data?
A normal force restart is designed to restart the device and does not normally erase personal data. An erase or restore is different and should be approached only after backing up.
Should I replace the battery immediately?
No. Random restarts can have software, storage, accessory, temperature or hardware causes. Check the evidence first rather than replacing parts by guesswork.