Before worrying, look at what the phone was doing. Charging, updating iOS, restoring a backup or running GPS for a long time heat the iPhone on purpose, and that passes on its own (Solution 1). If it gets hot sitting idle, screen off and untouched, the cause is usually an app stuck in the background (Solution 3) or a battery at the end of its life (Solution 8). Take the case off and get out of the sun before any test, because those two alone are enough to trigger the temperature warning (Solution 2). If the screen goes dark with a temperature warning, nothing is broken: the iPhone is protecting itself and comes back once it cools. Never speed up cooling with a fridge, a freezer or cold water.
What causes this problem
- Heavy continuous use: a 3D game, the camera recording at high resolution, GPS navigation with the screen on, or a long video call.
- Charging and using at the same time, especially with a fast charger, a thick case, or resting on a bed or sofa.
- Background work iOS does after an update, a backup restore or a device transfer: photo indexing, iCloud downloads and app reinstalls.
- A faulty app stuck in the background, using the processor non-stop even with the screen off.
- External heat: a car in the sun, the beach, a pocket against your body on a hot day. The iPhone was not built to run in a very hot environment.
- A worn or damaged battery, which heats up under light load and drains fast. It is the least common cause, but the most serious.
- Note what the iPhone was doing in the minutes before. Charging, updating, restoring a backup, GPS and video recording explain most cases and are not faults.
- Take the case off and leave the phone on a hard surface, away from sunlight and heat sources. Only test once it is back to normal temperature.
- Check battery health in Settings > Battery > Battery Health and Charging. Note the Maximum Capacity figure before touching anything else.
- In Settings > Battery, see which apps sit at the top of the usage list for the last 24 hours. That is the best clue to a stuck app.
- If the phone is hot enough to be uncomfortable to hold, if the battery is swollen, if the screen is lifting or there is an odd smell, stop here and get it serviced. Do not continue testing.
Solutions, in the order to try them
1Confirm whether the heating is normal for the device
This is the check that saves pointless work. The iPhone heats up on purpose in some situations, because it is pushing the processor and battery hard. In those cases the heat fades on its own a few minutes after the task ends, and there is nothing to fix.
- It is normal to heat up while charging, especially in the first minutes and with a fast charger.
- It is normal to heat up in the first hours after an iOS update, a backup restore or setting up a new iPhone: the system indexes photos and downloads data in the background.
- It is normal to heat up with GPS running in a car mount, with a 3D game, with long video recording and during video calls.
- It is normal to heat up on wireless charging, which loses more energy as heat than a cable does.
- Leave the phone idle with the screen off for 15 minutes. If it cools down and stays cool, it was normal use. If it stays hot while idle, go to Solution 3.
2Take the case off and get out of the heat
The case and the surroundings account for a large share of temperature warnings, and they are the quickest fix. The iPhone sheds heat through its body: a thick case, a battery case or resting on fabric block that path and the heat stays trapped inside.
- Remove the case whenever you charge for a long stretch or use the phone heavily.
- Do not charge on a bed, sofa, pillow or inside a bag. Use a desk or another hard surface.
- Never leave the iPhone on the dashboard or in the glovebox of a car parked in the sun. That is the most common temperature shutdown scenario.
- In a car mount with GPS running, aim an air vent at the phone and avoid charging and navigating at the same time on a hot day.
- To cool it down, leave it somewhere cool and shaded. Do not use a fridge, a freezer, ice or water: the sudden temperature change creates condensation inside the phone and can damage the electronics.
3Find out which app is eating the processor
If the iPhone heats up while idle with the screen off, there is almost always an app stuck in the background. The battery usage list is the most direct way to find the culprit, and background activity is usually the part that matters.
- Open Settings > Battery and wait for the graph to load.
- Choose the Last 24 Hours view and look at the app list below the graph.
- Tap Show Activity to see how long each app spent on screen and how long it spent in the background.
- Be suspicious of any app with a lot of background time and little screen time. That is the signature of a stuck app.
- Close the app from the app switcher: swipe up from the bottom and pause in the middle of the screen (or double-press the Home button on models that have one), then flick the app card upwards.
- If it heats up again, delete the app and watch for a day. If the heat goes away, that app was the problem: reinstall it and keep it updated, or find a replacement.
4Restart the iPhone properly
A system process can hang and keep looping, and a restart clears it without erasing anything. It is worth doing before deeper changes, because it fixes the cases where no specific app shows up in the usage list.
- On models with Face ID: hold the side button together with either volume button until the power-off slider appears.
- On models with a Home button: hold the side (or top) button until the slider appears.
- Slide to power off, wait 30 seconds, then turn it on by holding the side button until the Apple logo appears.
- If the phone is frozen and unresponsive, force a restart: press and release volume up, press and release volume down, then hold the side button until the Apple logo appears.
5Cut down on background work
Background app refresh, always-on location and heavy syncing keep the processor awake even with the screen off. Trimming what you do not use reduces background heating without taking away anything important.
- In Settings > General > Background App Refresh, turn off apps that do not need to refresh on their own. Social media and shopping apps are the first candidates.
- In Settings > Privacy and Security > Location Services, switch everything set to Always over to While Using the App, except navigation and trackers you genuinely rely on.
- In Settings > Photos, check whether the iCloud sync has finished. A large library uploading for the first time heats the phone for hours, and that is expected.
- In Settings > App Store, leave automatic updates for when the phone is charging overnight.
- If the problem started right after switching iPhones, give it a day or two before concluding something is wrong. The data migration keeps running in the background.
6Review the charger, the cable and how you charge
A cheap generic charger or a cable with a damaged connector generates heat right at the connector and can warm the phone for no good reason. If the heat is concentrated at the bottom, near the cable port, this is the first place to look.
- Test with a different cable and a different power adapter, ideally the originals or a known brand certified for iPhone.
- Look into the charging port against the light. Compacted dust and lint at the bottom ruin the contact and cause heat. Clean it with a wooden toothpick, phone powered off, never with a metal object.
- Avoid charging inside a car on a hot day with the phone on the dashboard in direct sun.
- If you use wireless charging, check that the phone is properly centred on the pad. Off centre, the pad keeps pushing and runs much hotter.
- Do not game or watch video while the phone is on fast charge. That is the combination that generates the most heat.
7Update iOS and, if needed, restore the phone
System bugs that cause high power draw are usually fixed in updates. When nothing else explains the heat, a restore clears out corrupted settings and data that carry the problem from one device to the next through the backup.
- Install the latest iOS version in Settings > General > Software Update, with the phone charging and on Wi-Fi.
- Let the phone rest for a few hours after the update before judging the result: heat right after an update is expected.
- If it persists, make a current backup to iCloud or a computer, then go to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings.
- Warning: this step wipes everything on the phone. Confirm the backup finished before continuing.
- During setup, first try it as a new iPhone, without restoring the backup, and use it that way for a few hours. If the heat disappears, the problem was an app or setting in the backup, not the hardware.
8Assess the battery and get it serviced
A worn battery heats up under light load, drains fast and sometimes shuts the phone down with charge left. When the earlier steps change nothing, this is usually where the problem is, and a replacement settles it for good.
- Check Maximum Capacity in Settings > Battery > Battery Health and Charging. A low figure, together with heat and shutdowns, points to a battery at the end of its life.
- Look on that same screen for any system message about the battery needing service or maintenance.
- If the back or the screen is lifting, if the phone is deformed or too hot to touch, stop using it and take it in. A swollen battery is a real hazard.
- Prefer authorised service or a trusted shop using quality parts. A cheap aftermarket battery tends to repeat the problem within months.
- If the heating started after a drop or contact with water, say so at the service centre: it changes the diagnosis considerably.
Applies to
| System | Status |
|---|---|
| iPhone on iOS 17 and iOS 18 | Confirmed |
| iPhone on iOS 15 and iOS 16 | Confirmed |
| iPad on iPadOS | The Battery and Background App Refresh screens work the same, with similar menu names |
Menu names can change slightly between versions. If a step above does not match what you see on screen, the official support page from the manufacturer has the most current wording for your version.
Frequently asked questions
Last checked: Aug 1, 2026 · We review this guide whenever the manufacturer changes the process.