Phone Keeps Restarting by Itself? Why It Reboots at Random — and How to Fix It (iPhone & Android)

It's an unsettling thing to watch. You're halfway through a text, a call, or a video and the screen goes black, the maker's logo appears, and a minute later your phone is back at the lock screen as if nothing happened — except whatever you were doing is gone. Sometimes it does it once a day; sometimes every few minutes; sometimes it happens overnight and you only notice because your alarm didn't go off. And because there's no error message to explain it, it feels random and personal, like the phone has simply decided to quit on you.

It almost never is random. A phone that restarts by itself is its software or its hardware hitting a problem serious enough that rebooting is the safest response — and the causes come from a short, findable list: a misbehaving app, a shaky software update, heat, low storage, or, most commonly of all and the one people never guess, a tired battery. The good news is that you can work through them in order, and most fixes are free. One thing to skip on your way in: the "iOS system recovery" and "Android repair" apps advertised all over these search results. A phone rebooting on its own is almost always a specific app, update, or hardware problem, and no downloaded tool fixes a worn-out battery or a dirty charging port. Everything below is a real step, and nearly all of it costs nothing.

First: is it really restarting — or stuck, or dead?

These feel like the same problem but they point in very different directions, so be precise about what yours actually does. A phone that works fine, reboots without warning, and then comes back and works again is what this guide is for — a spontaneous restart, usually caused by software, heat, or the battery. A phone that keeps cycling through the maker's logo over and over and never reaches the home screen is stuck in a boot loop, which is a deeper problem; our guides to an Android that won't get past the logo and an iPhone stuck on the Apple logo cover that one, because the fix is different. And a phone that shuts off and refuses to come back on at all is a no-power problem, covered in those same two guides.

One more distinction worth making up front: does it restart on its own, or does it freeze first and then you hold the button to force it back? A phone that locks up and stops responding is a freeze, which leans more toward storage, memory, or one bad app — closer to a phone that's slow and stuttering than to a clean spontaneous reboot. If yours truly restarts by itself, with no input from you, read on.

Rule out the one that isn't a fault: a scheduled restart

Before you chase a problem, make sure there is one. Many Samsung Galaxy phones have a built-in "Auto restart" feature that reboots the phone on a schedule — often in the small hours of the morning — to keep it running smoothly, and plenty of people have it switched on without realising. If your phone reboots at roughly the same quiet time each day or week and is perfectly fine otherwise, that's almost certainly it, not a fault. Check under Settings > Battery and device care > tap the three-dot menu > Automation > Auto restart at set times. A scheduled restart only fires when the screen is off, the phone isn't in use, the battery is above 30%, and there's no SIM lock — so it should never interrupt you. Turn it off if you don't want it, or leave it on; either way, mystery solved.

iPhones don't have a scheduled-restart setting, so if an iPhone is rebooting on its own it's worth taking more seriously as a real fault. And on any phone, a restart that happens while you're actively using it — mid-call, mid-scroll — is not a scheduled one, so keep going.

Start simple: force restart, then update

Two quick, free steps clear a surprising share of these. First, do a proper forced restart to flush whatever state the phone got stuck in — this is different from the phone rebooting itself and can settle a temporary glitch. On an iPhone (8 and newer, including all Face ID models): press and release Volume Up, press and release Volume Down, then press and hold the Side button until the Apple logo appears — keep holding past the power-off slider. On most Android phones, including Samsung and Pixel, hold the Power and Volume Down buttons together for about ten seconds until it restarts. (A few older phones use a different combo; if yours doesn't respond, check your model.)

Second — and this is a genuine top cause — check for a software update. A buggy operating-system release can make a specific phone reboot repeatedly until the maker ships a follow-up patch, so an out-of-date phone is sometimes the whole problem, and updating is the cure. On iPhone go to Settings > General > Software Update; on Samsung, Settings > Software update > Download and install; on other Android phones, Settings > System > System update. Install anything waiting, restart, and watch. Keep the flip side in mind too: if the reboots started the day after an update installed, the update is your suspect — a newer patch usually follows quickly, so update again rather than staying stuck on the bad build, and if your carrier or maker has pulled it, give it a few days.

A bad app is a classic cause — here's how to catch it

A single misbehaving app — often one that recently updated, or one downloaded from outside the official store — can crash hard enough to take the whole phone down with it. The tell is timing: if the reboots began right after you installed or updated a particular app, or they only happen when you open one specific app, you've likely found it. Delete that app and see if the phone steadies; you can always reinstall it once a fix ships.

When it's not obvious which app is to blame, each platform gives you a way to find out. On Android, restart into Safe Mode, which loads only the software that came with the phone and disables everything you installed: press and hold the Power button (or hold the on-screen "Power off"), then touch and hold "Power off" and choose Safe mode. If the phone stops rebooting in Safe Mode, a downloaded app is the culprit — restart normally and uninstall recent apps one at a time, testing after each. iPhones don't have a Safe Mode, but they keep a crash log you can read: go to Settings > Privacy & Security > Analytics & Improvements > Analytics Data and scroll the list. If you keep seeing entries with the same app's name, that app is crashing repeatedly and is your suspect — delete and reinstall it. (Entries that mention "JetsamEvent" instead point at the phone running out of memory, which usually means storage is too full — see the next step.)

Free up storage and reset settings

A phone with almost no free storage becomes unstable — apps crash, the system struggles, and sudden reboots become more likely — so if you're running near empty, clearing space is a real fix, not just housekeeping. Aim to keep roughly ten percent of the phone's storage free. Our guides to freeing up space on an iPhone and on an Android walk through exactly what's safe to delete; the biggest wins are usually old videos, offloading apps you don't use, and clearing downloads and photo backups you've already saved elsewhere.

If the phone is up to date, storage is fine, and no single app seems to blame, an iPhone has a useful in-between step before anything drastic: Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings. This resets your system settings (Wi-Fi passwords, layout, permissions) back to defaults but does not erase your photos, apps, or data — so it's a low-risk way to clear a corrupted setting that might be triggering the reboots, without wiping the phone. It's worth trying before you consider a full erase.

The overlooked cause: a tired or swollen battery

This is the one people almost never guess, and on an older phone it's the most likely answer of all. As a lithium battery ages it struggles to deliver power smoothly under sudden demand — opening the camera, a game loading, the screen jumping to full brightness — and when it can't keep up, the phone shuts down or restarts to protect itself. The classic pattern is a phone that reboots or dies unexpectedly, often when there's still 20–40% showing on the battery, and that also drains faster and feels sluggish. On an iPhone you can check directly: Settings > Battery > Battery Health & Charging. A Maximum Capacity that has dropped well below 80%, or a note that "performance management" has been applied after an unexpected shutdown, is a strong sign the battery is the cause. Android hides the exact figure on most phones, but the physics are identical — a two-or-three-year-old phone that restarts itself and dies fast is telling you the same thing.

The good news is that a battery is one of the cheaper, more worthwhile repairs there is, and a fresh one often makes an older phone feel new again — far better value than replacing the whole phone over a fault a battery swap fixes. There is one battery symptom to treat as urgent, though: if the phone's back or screen looks like it's bulging or lifting apart, or the phone rocks on a flat table, the battery is swelling. Stop using and charging it and get it replaced promptly — a swollen lithium battery is a safety issue, not just a performance one.

Heat, the charging port, and physical damage

Heat causes the same protective shutoff. If the phone gets hot — in a car on a summer afternoon, in direct sun, on the dashboard as a GPS, or while charging and gaming at once — it will throttle and can restart or power off to avoid damage. Southern California summers make this a real, seasonal cause: a phone left on a hot dashboard in the Coachella Valley can hit its limit doing very little. If your reboots happen when the phone is warm to the touch, treat it as heat — take the case off, get it out of the sun, stop charging while you use it, and let it cool before deciding anything else is wrong. Our guide to an overheating phone goes deeper.

Hardware around the battery matters too. A dirty or damaged charging port can cause restarts specifically while charging — lint packed into the port, or a frayed cable, interrupts the power feed. Look into the port with a light and gently clear any lint with a wooden or plastic toothpick (never metal), and try a different, good-quality cable and charger. And be honest about history: if the reboots started right after the phone was dropped or got wet, treat it as physical damage — a knock can loosen an internal connector and moisture can corrode one, and no software step fixes that. If it took a spill, our guide on what to do after a phone gets wet covers the right first moves.

Last resorts: back up, then reset

If you've updated, ruled out apps, freed up storage, checked the battery, and the phone still reboots on its own, the deepest software fix is a factory reset — but back up first, because it erases everything on the phone. Make sure your photos and data are safely in iCloud or Google (or copied to a computer) before you start; a reset is not a backup. On iPhone: Settings > General > Transfer or Reset iPhone > Erase All Content and Settings. On Android: Settings > System > Reset options > Erase all data (factory reset), or search Settings for "factory reset." Set the phone up again and, at first, add your apps back gradually rather than restoring everything at once — that way, if one app was the cause, it won't come straight back with the restore.

There's a gentler middle step on some Android phones, mainly Samsung: wiping the cache partition from recovery mode clears the system's temporary files without touching your data or apps, and can settle instability after a rocky update. Not every phone still offers it, and the button combo to reach recovery varies by model, so look up the exact steps for yours. If a full reset doesn't hold — the phone keeps rebooting even after a clean wipe and setup — that's strong evidence the cause is hardware (the battery, or a board-level fault from a drop or spill), and it's time for a repair rather than more software steps.

How we can help

The honest short version: don't pay for a "phone repair" or "system recovery" app for a phone that restarts itself — none of them can fix the real causes. Work through it in order instead: rule out a scheduled restart, force-restart and update, hunt for a bad app (Safe Mode on Android, the Analytics crash log on iPhone), free up storage, and — especially on an older phone — check the battery, because a tired one is the single most common reason a phone reboots at random. Most people find the culprit for free.

When it comes down to hardware — a worn or swollen battery, a damaged charging port, or a fault left behind by a drop or a spill — that's where we come in. We help people across Southern California and the Coachella Valley diagnose exactly why a phone keeps restarting, do the battery or port repair when that's the answer, and tell you honestly when a phone is worth fixing versus replacing. Because we don't sell software subscriptions, we've no reason to point you at anything but the actual fix.