Why Does My iPhone Keep Restarting by Itself? 9 Fixes

An iPhone that restarts by itself is more than a nuisance. It can interrupt calls, lose half-typed messages, and make you worry that the phone is dying. The restart loop can happen every few minutes or just a few times a day, and it rarely fixes itself.

The causes fall into two groups. Software problems, such as a buggy app, a corrupted update or a full storage drive, are the most common and the cheapest to fix. Hardware problems, usually a worn-out battery that can no longer supply steady power, need a repair.

This guide takes you through the checks in the right order, from quick software fixes to the battery test that tells you whether the phone needs professional help.

Quick Answer

An iPhone that keeps restarting is usually caused by a failing battery, a buggy app, low storage, or a glitchy iOS update. Start by checking battery health in Settings, Battery, Battery Health. Below 80 percent maximum capacity points to the battery. Then update iOS, free up storage, and reset all settings. If restarts continue after a clean restore, it is almost certainly a hardware fault.

Check the Battery Health First

Restart loops are famous as a battery symptom. As an iPhone battery ages, it struggles to deliver peak power, and the phone shuts down or restarts to protect itself, sometimes even at 40 or 50 percent charge.

1. Open Settings and tap Battery.
2. Tap Battery Health and Charging (called Battery Health on older iOS versions).
3. Look at Maximum Capacity. Below 80 percent means the battery is significantly degraded.
4. Check whether a message says the battery needs service or that an unexpected shutdown occurred.

If the capacity is low or a service message appears, a battery replacement is the real fix. Everything else in this guide is worth trying first, but no setting can repair a worn-out battery.

Update iOS and Your Apps

A restart bug inside iOS itself, or in one popular app, often spreads widely after an update and is fixed quietly in the next one. That is why updating is step two.

1. Connect to Wi-Fi and plug the phone into power.
2. Go to Settings, General, Software Update and install any available update, such as the latest iOS 27 point release.
3. Open the App Store, tap your profile picture, and update all apps.
4. Delete any app that was installed or updated on the day the restarts began, and test for a day without it.

If the phone restarts even during the update, do not worry. Updates resume safely, and you can also update through a computer using Finder or iTunes.

Free Up Storage Space

An iPhone with almost no free space behaves strangely: apps crash, updates fail, and the system restarts under pressure. Apple suggests keeping at least 1 GB free, and more is better.

• Open Settings, General, iPhone Storage to see what is using space.
• Delete large videos, old downloads in streaming apps, and games you no longer play.
• Offload unused apps, which removes the app but keeps its data.
• Clear the browser cache in Settings, Safari, Clear History and Website Data.

While you are there, note any single app using a surprising amount of storage. Corrupted app data is a quiet cause of crash loops, and reinstalling that app often ends them.

Reset All Settings (Without Erasing Data)

If updates and storage are fine, a damaged settings file may be behind the restarts. Resetting all settings is safe: it returns system settings to defaults but keeps your photos, apps and files.

1. Go to Settings, General, Transfer or Reset iPhone.
2. Tap Reset, then Reset All Settings.
3. Enter your passcode and confirm.
4. Reconnect to Wi-Fi afterwards and re-apply personal settings like wallpapers and ringtones.

Look for a Pattern and Check the Crash Logs

When the restarts happen tells you a lot. Restarts only while charging point to the cable, adapter or charging port. Restarts during one game point to that app or to overheating. Restarts at random point to the battery or the system itself.

You can even read the evidence: in Settings, Privacy and Security, Analytics and Improvements, Analytics Data, look for entries named ‘panic’ with recent dates. Frequent panic logs mean the system is crashing hard, which Apple technicians take seriously. Our guide to putting an iPhone into recovery mode explains the last-resort restore if you reach that stage.

The Special Case: Restarting After Water or a Drop

Timing matters when you diagnose restart loops. If the restarts began immediately after the phone was dropped, got wet, or was repaired, skip the software steps and think hardware first. A drop can crack a solder joint on the logic board or damage the battery connector, so the phone loses power for a split second whenever it flexes or warms up. Water is worse: corrosion grows over days, which is why a phone can survive a soaking and then start restarting a week later.

Accessory faults belong in this category too. A failing pair of wired earphones, a damaged charging cable shorting intermittently, or a swollen battery pressing on internal connectors can all trigger restarts that stop the moment the accessory is removed or the case comes off. Test the phone bare, with no cable and no accessories, for a full day before concluding anything.

If restarts follow physical damage, back up immediately while the phone still runs in stretches, because these faults almost always worsen. Then book a diagnosis: technicians can read the panic logs, test the battery’s connection and health, and tell you honestly whether a battery swap or a board-level repair makes economic sense for the phone’s age.

Common Mistakes and Helpful Tips

• Do not jump straight to a factory reset. Work through battery, updates, storage and settings first; they fix most cases.
• Cheap third-party batteries are a common hidden cause. A poor quality replacement battery can cause restarts within months.
• Remove the case and test for a day if restarts happen during heavy use. Trapped heat triggers protective shutdowns.
• Back up the phone now, while it still stays on long enough. A restart loop can get worse, and a backup protects your data.

Apple publishes guidance for unexpected restarts too. The official Apple advice if an iPhone keeps restarting walks through updates, SIM removal tests and when to contact support.

Conclusion

An iPhone that restarts by itself is usually asking for one of four things: a healthier battery, an iOS or app update, more free storage, or a settings reset. Work through those checks in order and the restarts stop in most cases. If the phone still loops after a clean restore through a computer, treat it as a hardware problem and book a battery or logic-board diagnosis with Apple. Either way, back up today, before the loop gets worse.

Frequently Asked Questions

Can a virus make my iPhone keep restarting?

It is extremely unlikely. iPhones that have not been jailbroken very rarely get malware. Restart loops are almost always caused by the battery, a buggy app, low storage, or a damaged iOS installation, so check those first.

Why does my iPhone restart while charging?

Suspect the cable, adapter or a dirty charging port first, because faulty power delivery makes the phone unstable. Try the original Apple cable and a different adapter. If restarts happen with every charger, the battery itself is the likely cause.

Will resetting all settings delete my photos?

No. Reset All Settings only returns system settings such as Wi-Fi passwords, wallpapers and notification preferences to defaults. Your photos, messages, apps and files stay in place. It is different from Erase All Content and Settings, which wipes the phone.

How much does an iPhone battery replacement cost?

Prices vary by model and country, and newer models such as the iPhone 17 and 18 cost more than older ones. Apple lists current prices on its support website, and a genuine replacement restores stability and usually ends battery-related restart loops completely.

My iPhone restarts every few minutes and I cannot do anything. What now?

Connect it to a computer and use recovery mode to update iOS. If the update fails, restore the phone and set it up from a backup. A phone that still restarts after a clean restore, with no apps installed, has a hardware fault and needs repair.