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Why Your Phone Overheats and How to Cool It Down Safely

October 9, 2026 · Marion Phone Repair

All phones generate heat during use. The processor, battery, and screen all produce warmth, and that is normal. The problem starts when the phone gets uncomfortably hot to hold, displays a temperature warning, shuts down on its own, or stays warm even when you are not using it. These symptoms mean something is pushing the hardware past its thermal limits, and ignoring it risks permanent battery damage.

Normal warmth vs actual overheating

Understanding the difference prevents unnecessary worry and helps you catch real problems early:

• Normal: the phone feels warm during a long video call, while gaming, while using GPS navigation, or while charging. The warmth is distributed across the back of the phone and is not uncomfortable to hold
• Concerning: the phone is too hot to hold against your face or in your hand. The camera flash is disabled. Apps start closing on their own. The screen dims unexpectedly. Charging slows to a crawl
• Dangerous: the phone displays a temperature warning and locks you out until it cools down. The back of the phone is visibly bulging (swollen battery). The phone smells like burning plastic or chemicals

If the back of the phone is bulging or you smell something burning, stop using it immediately, do not charge it, and keep it away from flammable materials. A swollen battery is a safety hazard that requires professional removal.

What causes phones to overheat

Direct sunlight and hot environments

Leaving a phone on a car dashboard, on a beach towel, or in direct sunlight can push its internal temperature past 45 degrees Celsius (113 Fahrenheit). At that temperature, lithium-ion batteries start degrading permanently. The phone's thermal management system will throttle performance and eventually shut the phone down to protect itself, but the battery damage from repeated heat exposure accumulates over time.

Charging and using the phone simultaneously

Charging generates heat from the battery. Using the phone generates heat from the processor. Doing both at once doubles the heat output in a small, sealed device. This is especially problematic with fast charging, which pushes more energy into the battery at a higher rate. If you need to use your phone while it is charging, switch to a slower charger or remove the case to help it dissipate heat.

Processor-intensive apps

Gaming, video recording (especially 4K), augmented reality apps, video editing, and live streaming all push the CPU and GPU to their maximum for extended periods. Flagship phones handle this better than budget phones because they have larger heat spreaders and more efficient processors, but even high-end phones will throttle performance during prolonged heavy use.

Background processes and runaway apps

An app stuck in a loop, a failed software update, or a background process consuming 100 percent of the CPU can make the phone hot even when the screen is off. This is one of the less obvious causes because you may not realize anything is running.

To check on iPhone: go to Settings, Battery, and look at the battery usage by app over the last 24 hours. An app consuming a disproportionate amount of battery in the background is likely the culprit.

To check on Android: go to Settings, Battery, and look for apps with unusually high usage. Samsung phones also show this under Device Care, Battery.

Poor cellular signal

When your phone struggles to maintain a cellular connection (one bar or constantly switching between towers), the radio hardware works harder and generates more heat. This is common in rural areas, buildings with thick walls, or while traveling.

Old or degraded battery

As lithium-ion batteries age, their internal resistance increases. Higher resistance means more energy is wasted as heat during both charging and discharging. If your phone runs noticeably hotter than it did when new and the battery health is below 80 percent, the battery itself is the heat source.

Thick or insulating cases

Phone cases trap heat. Heavy-duty cases with thick rubber or silicone insulation can raise the phone's operating temperature several degrees because the heat has nowhere to go. This matters most during charging and heavy use.

How to cool down an overheating phone

1. Move it out of direct sunlight or any hot environment. Put it in shade or bring it indoors
2. Remove the case. Let the phone's body dissipate heat directly into the air
3. Stop charging. Unplug the charger immediately if the phone is hot
4. Close all apps. On iPhone, swipe up from the bottom and swipe away all open apps. On Android, tap the recent apps button and close all
5. Turn off unnecessary radios. Disable Bluetooth, Wi-Fi, GPS, and mobile hotspot. Or simply turn on Airplane Mode for a few minutes
6. Set the phone on a hard, cool surface. A table or countertop conducts heat away from the phone faster than fabric or cushions
7. Wait. Give it 10 to 15 minutes to cool naturally

What not to do

• Do not put it in a refrigerator or freezer. Rapid temperature changes cause condensation to form inside the phone, which can short-circuit internal components and cause water damage
• Do not blow on it with compressed air. This can push moisture into the phone
• Do not put it in front of an AC vent or fan blowing cold air. The temperature difference can still cause internal condensation

Prevent overheating long-term

• Avoid charging past 80 percent when possible. Both iPhone (Optimized Battery Charging) and Android (Adaptive Charging on Pixel, Protect Battery on Samsung) have settings that limit charging to 80 percent by default. This reduces heat and extends battery lifespan
• Do not leave the phone in a parked car. Interior temperatures can reach 60 degrees Celsius (140 Fahrenheit) in summer, well past the phone's safe operating range
• Use a thinner case or remove it during charging. If your phone runs warm during regular charging, the case may be contributing
• Keep the software updated. OS updates often include fixes for bugs that cause excessive CPU usage and battery drain
• Close background apps you are not using. Apps running navigation, streaming, or syncing in the background add unnecessary heat
• Use Wi-Fi instead of cellular when available. The Wi-Fi radio uses less power than the cellular radio, generating less heat

When overheating means the battery needs replacing

If the phone overheats during light use (texting, browsing, checking email), the battery is likely the problem. Check battery health:

• iPhone: Settings, Battery, Battery Health and Charging. Below 80 percent Maximum Capacity means the battery is worn
• Samsung: Settings, Battery and Device Care, Battery, Battery Status
• Pixel: Settings, Battery, Battery Health

A battery replacement restores normal thermal behavior and brings back the battery life the phone had when new.

Phone overheating help in Marion

Marion Phone Repair diagnoses overheating phones and replaces worn batteries for iPhones, Samsung Galaxy, Google Pixel, and other models. If your phone runs hot during normal use, we can check the battery health, test for software issues, and replace the battery if needed. Most battery replacements are completed same-day.