Why does my phone get hot?

A common question with no single answer, we’re here to help you super sleuth your way to the bottom of this hot topic (couldn’t help myself). Note that this doesn’t include your phone getting warm from time to time, which is completely normal; it is an electronic device after all, and electronic devices work via the movement of electricity, which creates heat — simple physics. But if your phone is regularly turning up the heat to the point where it’s uncomfortable to hold, there could be a more serious problem going on that could ultimately speed up your phone’s aging process.

Where is the heat coming from?

When phone temperature rises, the most probable culprits are either the battery, processor, or screen. Each of these components can generate heat; chemicals inside your phone’s battery create electricity, the processor transfers information at high speeds (like a computer), and your phone’s screen emits light. So how can you pinpoint what’s causing the problem? While not an exact science, you can make an educated guess about why your iPhone or Android phone is heating up based on where the heat is coming from.

Back of the phone

If the back of your phone is getting hot, the problem may be an overheating battery. Most modern mobile phones use Li-Ion (lithium-ion) batteries that, despite their size, pack a powerful punch. Li-Ion batteries are generally safe, but malfunctions do sometimes occur, as seen with the Samsung Galaxy Note 7 battery explosions. A hot battery could also be a sign that it needs to be replaced.

Bottom of the phone

See if the bottom of the phone gets hot when charging — if so, the problem might be with the charger. Whether you use an iPhone or Android, the most reliable charger will be from your phone’s manufacturer. But, contrary to popular belief, third-party chargers are also fine as long as they’re from a reputable source.

Above the battery, by the speaker, or the screen

If you notice your phone is getting hot somewhere besides the battery or the bottom where it connects to the charger, then explore other possible causes that could be either related to the phone itself, or to external factors.

Hot vs. warm — what’s the difference?

Now before you start jamming a thermometer into your phone’s charging port, understand that a ‘warm’ phone is not the same as a ‘hot’ phone. Generally, a phone’s internal temperature can reach 37-43 degrees Celsius (98.6-109.4 degrees Fahrenheit) and still be considered normal.

If you’re using an Android phone, you can install the nifty AIDA64 app, which will give you a ton of information about your phone’s hardware and software, including a temperature report. While Apple has expanded the information you can see in the “Battery Health” menu in its latest iOS 12.3 update, this does not include a temperature reading. However, since we’ve already established that some phone heat is normal, it’s better to determine overheating based on how often you notice your phone getting hot, or if the temperature is physically uncomfortable. Your phone should not be getting hot several times a day, or for seemingly no reason.

Causes of phone overheating

There are several, totally normal (and harmless) reasons why your phone may need to use more power than usual, causing it to warm up a bit. These include:

1. Gaming for long periods of time

If you haven’t found yourself hours deep into a Candy Crush or Snake vs. Block marathon, then you’re either lying or you’ve somehow never had to take public transit. The sheer breadth of available mobile app games is arguably one of the top reasons for buying a smartphone. However, high-intensity gaming apps use your phone’s central processing cores in addition to the graphics processing unit, which can make your phone warm up.

2. Streaming content

Similar to the gaming scenario, watching YouTube or Netflix for hours via your Android or iPhone is another surefire (get it?) way to overwork your phone’s processor, as it has to load the video data and keep the display active for a prolonged period of time.

3. Your settings aren’t optimal

Your phone’s settings also impact how much energy it’s using. Screen brightness on full blast? Animated wallpaper? Widgets, widgets everywhere? Consider turning off (or down, in the case of screen brightness) unnecessary settings to lighten the load on your phone’s CPU.

Other reasons may not be related to your phone’s normal processes, but are still relatively easy to fix:

4. Environmental factors

Prepare to have your mind blown, but leaving your phone sitting outside in the sun or in your car on a hot day can cause it to overheat (*GASP*). This will also prevent the touch screen from working properly and cause the battery to drain faster. In addition to sun and heat exposure, water damage can also be a possible cause of phone overheating.

5. App updates

If an app has a bug or other problem, it may cause your phone to overheat by overusing your device’s processor. Keeping your apps updated is important because updates often include bug fixes.

6. Software updates

Rarely, a phone may overheat either after an update, or because there was a bug in the OS that required fixing through the update.

When there’s a bigger problem

While there are many plausible explanations for why your phone is getting hot in here, it’s better not to assume the problem is an easy fix. An overheating phone can also be a sign that your phone is infected with malware. Malware often consumes a ton of your phone’s ram and CPU power, which causes the phone to overheat. Some types of malware are even capable of physically damaging your phone.

With the explosion of Bitcoin, cryptocurrency has moved to the forefront of hackers’ interest. Last year, a strain of Trojan malware called Loapi infected Android phones by disguising itself usually as a fake antivirus app in the Google Play store. Loapi malware was used by hackers to secretly mine Monero cryptocurrency. This maxed out the processor’s computing power and caused the device to overheat, causing the phone’s battery to noticeably bulge just two days after the initial infection.