Phone battery draining fast? Malware is one of 8 possible factors - how to tell for sure

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ZDNET's key takeaways

• There are many possible causes of your phone's battery degradation.
• Identifying the reasons for deteriorating battery life can be challenging
• Sometimes the culprit is malware: How to identify and remove it.

Lately, is your smartphone consuming more power more quickly, and your battery life deteriorating? Could malware be responsible? OK, let's take a deep breath. Before we walk you through the steps to investigate and fix a malware problem on your phone, let's look at some other possible culprits behind your power issue.

Batteries age, get damaged, and become less efficient as we repeatedly charge and drain them. At first glance, high power consumption and a steep drop in the number of hours a full charge lasts might raise the alarm that something is on your smartphone that shouldn't be there. Mobile malware is designed to stay hidden, which means your phone battery could be dying as malicious software quietly drains your power without any signs, notifications, or other strange behavior. 

Also: This silent Android feature scans your photos for 'sensitive content' - how to uninstall it

However, there are many other reasons why your device is not operating as it should: lithium-ion batteries die, need to be replaced, and won't last forever. There are also plenty of other environmental factors, app changes, and settings to consider before you decide to purchase a new battery or switch to a different smartphone altogether.

Here are 7 things to consider. Already looked into everything on our checklist? Scroll down for our tips on identifying and removing malware from your device.

1: Check your battery usage

The first step in solving a problem is understanding it; let's check how your battery is being used, and by what. 

The way to check your battery usage on Android and iOS is very similar. Hop into settings, select the battery tab, and -- depending on the make and model of your device -- select an option such as battery usage or apps. On this screen, you can explore which apps are using the most battery (and when).

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Keep in mind that batteries are only optimal for around three years, and battery capacities vary. Lithium-ion batteries will always degrade over time, so you will find that performance suffers every year you use the same hardware. 

It might not be by much at the start, but if you suddenly notice your battery isn't lasting nearly as long as it should, consider whether you've had to charge it more and more over the years. You might already have your answer as to the cause of your dying battery.

2. Consider your apps and their permissions

You should also look for any unfamiliar apps on your mobile device. If you spot any app you are unfamiliar with or no longer use -- especially if it tends to consume a lot of power -- it might be the right time to delete it.

Also: We know what's making your phone's battery drain so quickly

For example, let's say you've recently downloaded a mobile game. You then notice it is constantly running in the background and using more power than you might expect. If you're constantly running a power-hungry mobile game, an AI assistant, or leaving TikTok live streams open for hours, this will reduce your battery life.

I picked up my Samsung Galaxy Z Fold6 at launch in 2024, and while it is only a few years old, it now frequently consumes 10% to 15% of my battery during a 20- to 30-minute FaceTime call, when it used to be far more efficient. 

You should also check app permissions to see if you've granted your apps more control than they need, as this could contribute to overall battery consumption -- especially if these apps are allowed to run in the background, are constantly syncing, or are always connected to phone functions such as location sharing. 

3. Check your phone settings

These are some of the most important smartphone settings that can contribute to poor battery life:

Also: 12+ iPhone settings you can change to noticeably improve its battery life (iOS 26 and older)

• Screen brightness: If it's set to maximum, it can reduce battery life.
• Always-on displays: Enabling an always-on display will use more battery than allowing your smartphone's display to turn off after a set period (also known as a screen timeout). 
• Battery saver: Battery-saving options limit battery-hungry phone functions such as syncing, HDR display use, and location checks, while also reducing your screen brightness. Enabling this function can keep your phone going for longer.
• App syncing: Allowing apps to run in the background and frequently sync with services -- such as email and social media -- could reduce the hours of battery life you can expect on a single charge. 
• Animated wallpapers and themes: Animated graphics, wallpapers, and themes -- especially when displayed at high resolution -- will contribute to a loss of battery life. It might not be much, but over the course of a day with an always-on display, it could be more than you think.
• Location services: Allowing location services and GPS pings to run continuously will drain your battery over the course of the day.
• Wearables and Bluetooth: A factor some of us might overlook is the Bluetooth connection between our smartphone and our wearable, such as a smartwatch. If this connection is active daily, the constant communication between the two devices may impact your battery. 

4. Update your operating system and apps

Ensure all your apps and the operating system are up to date. Fixes are frequently pushed to address software issues that could affect your handset's performance. This includes system apps using too much power, excessive synchronization, and OS optimization to reduce battery demand. 

5. Consider environmental factors

If your smartphone has been exposed to direct sunlight and hot or cold temperatures for an extended period, your battery may be affected. 

Also: I changed 12 settings on my Android phone to extend its battery life by hours

Lithium-ion batteries naturally degrade over time, but extreme environmental conditions can accelerate this process. Hot cars, the beach, leaving your phone on the table at a cookout when the sun is shining bright -- if your smartphone becomes hot, your battery will drain. Furthermore, if it is too cold, this can affect the chemical reactions in your handset, reducing battery power and performance.

6. Is your hardware old or damaged?

Batteries simply don't last. The constant cycle of charging and recharging will, over time, reduce its performance. It might also be defective. 

If you've had your smartphone for a while, it might simply be time to replace the battery. In addition, if any water or other fluids have come into contact with your smartphone, it may have damaged its internal components -- including the battery. (Please don't microwave it; that myth will toast your battery far more than leaving it in the sun.)

7. How are you charging, and is it wireless?

Another factor to consider is how you are charging your device. As noted by power bank manufacturer Anker, a concern with wireless chargers is heat generation, as electromagnetic radiation can cause your smartphone to heat up, reducing battery performance.

You may also not realize it, but fully charging your device during cycles can also degrade your battery over time. It's best to keep the charge level between 20% and 80%. 

I'm still concerned. Could it be mobile malware?

Mobile malware is malicious software, usually disguised as a benign mobile app. Mobile malware can end up on your handset through phishing and by clicking links that download the software; by accidentally downloading apps online that have hidden, malicious functions; or installed quietly by someone with access to your smartphone without your knowledge, such as in cases of stalking or domestic abuse. 

Infrequently, malicious apps can end up in official app stores such as Google Play or Apple's App Store, even though both Apple and Google have stringent protections in place to prevent this. 

Also: The best mobile antivirus software: Expert tested and reviewed

If malware is installed on your smartphone, it may steal your username and password for online accounts; monitor your location, calls, and social media activity; record audio and video; destroy or steal your data; show you unwanted pop-ups; and even register you for premium calls & SMS services. 

Mobile malware is designed to remain hidden and operate quietly in the background, but unexpected battery usage can be a potential symptom. Trojans designed to steal your information are the most common mobile malware threats, but if you stick with official app stores and keep your phone updated, you will reduce the likelihood of encountering one. 

Found something strange? Delete suspicious apps immediately

If you're unsure about an app -- it's unfamiliar, or you simply don't use it anymore -- delete it. This is as simple as holding your finger down on the app icon and selecting the option to delete the app, or going into the apps section of your handset to remove it.

After you find and remove an app, change your passwords for any accounts connected to your smartphone, just to be safe. 

Run a malware scan

The next step is to run a malware scan on your smartphone. Malware scanners and antivirus programs run in the same way that they would on your desktop PC or laptop; they check the validity of your files and apps, analyze suspicious code, and warn you if you need to quarantine any apps.

Popular options include Bitdefender, Avast, and AVG. If you would like to view our favorites, check out our guide to mobile antivirus software.

Should I factory reset if I find mobile malware?

While most forms of malware can be eradicated with a factory reset, this is often the last resort. A factory reset will restore your phone to its default settings and delete all your apps, files, photos, videos, and contacts. You will also have to reinstall your favorite apps. 

Also: How to factory reset your Android phone without unlocking it first

Only consider this solution if you must. Basic mobile malware -- those that bombard you with adverts and pop-ups -- will likely be removed with a simple scan, but if you have become the victim of stalkerware, for example, a factory reset might give you more peace of mind. 

If you feel it is in your best interests, perform a factory reset. However, you could also consider taking your handset to a specialist who can deal with the infection -- or safely copy over your important files first.