Phones · Repair guide

How to fix a phone battery that drains fast

8 fixes, easiest first4 min readUpdated November 2026

Quick fix

Open the battery usage screen (Settings > Battery on iPhone, Samsung and Pixel) to find the app using the most power, update or limit that app, then restart the phone and turn on Low Power Mode, Power saving or Battery Saver.

What it means

Fast battery drain usually comes from one app or setting working hard in the background, a bright screen, weak signal, or the extra work a phone does for a day or two after a software update. If the drain started gradually over a long time, the battery itself may have worn out and need replacing.

Common causes

  • One app using a lot of power in the background
  • Indexing and setup work in the first day or two after a software update
  • A bright screen, long screen time or heavy gaming and video
  • Weak cellular or Wi-Fi signal making the phone work harder
  • Out-of-date apps or system software with known battery bugs
  • A worn battery that holds less charge than when new

How to fix it

Work down the list. Each fix is safe to try before moving on to the next.

01Find out which apps use the most batteryEasy

  1. On iPhone: open Settings > Battery and scroll down to see app and system activity. Tap View All Battery Usage and pick a day to see past days.
  2. On Android (Samsung): open Settings > Battery, tap the battery graph and look at the app list to see battery usage for each app.
  3. On Pixel: open Settings > Battery > Battery usage and tap View by apps.
  4. On Pixel 6 or later, you can also run Settings > Battery > Battery diagnostics > Battery draining too quickly.
  5. Note any app using far more than you would expect for how much you use it. Other Android phones: search Settings for 'battery usage'.

Why it helps: One misbehaving app causes most sudden battery drain, and these screens show which one it is.

02Restart the phoneEasy

  1. On iPhone: press and hold the Side button and either volume button until the slider appears, drag it to turn off, then press and hold the Side button to turn it back on. On iPhone with a Home button, hold the Side button alone.
  2. On Android (Samsung): press and hold Volume Down and the Side key together, then tap Restart and tap Restart again.
  3. On Pixel 6 or later: hold Power and Volume Up for a few seconds, then tap Restart. On Pixel 5a or earlier, hold Power for about 30 seconds.

Why it helps: A restart stops stuck background tasks that keep the processor busy and drain the battery.

03Update the phone and your apps, then give it a day after big updatesEasy

  1. On iPhone: go to Settings > General > Software Update and install any update.
  2. On Android (Samsung): open Settings, tap Software update and install any update shown.
  3. On Pixel: go to Settings > System > Software update.
  4. Update apps in the App Store or Google Play Store, since app updates often fix battery bugs.
  5. If the drain began right after a major update, keep the phone charged and give it a day or two. Phones often finish setup tasks such as indexing photos and data in the background after an update, which uses extra power for a short time.

Why it helps: Updates fix known battery bugs, and drain right after a big update often settles on its own.

04Turn on Low Power Mode, Power saving or Battery SaverEasy

  1. On iPhone 15 or later: go to Settings > Battery > Power Mode and turn on Low Power Mode. On iPhone 14 or earlier: Settings > Battery > Low Power Mode.
  2. On iPhone 15 Pro, iPhone 16 and later models, you can also turn on Adaptive Power in Settings > Battery > Power Mode. It can switch on Low Power Mode by itself at 20%.
  3. On Android (Samsung): go to Settings > Battery > Power saving and turn it on.
  4. On Pixel: swipe down from the top and tap the Battery Saver tile, or go to Settings > Battery > Battery Saver.

Why it helps: These modes cut background activity, visual effects and screen brightness so the charge lasts longer.

05Limit or remove the apps that drain powerEasy

  1. On iPhone: go to Settings > General > Background App Refresh and turn it off for apps that don't need to update in the background.
  2. On iPhone: in Settings > Privacy & Security > Location Services, set apps you rarely use to Never or While Using the App.
  3. On Android (Samsung): go to Settings > Battery > Background usage limits and add rarely used apps to Sleeping apps or Deep sleeping apps.
  4. On Android (Samsung): Settings > Device care > Optimize now closes background apps and clears unneeded files.
  5. On Pixel: in Settings > Battery > Battery usage, tap an app and check Allow background usage (keep Optimized on). To stop a misbehaving app now, go to Settings > Apps > See all apps, tap the app and tap Force stop.
  6. Uninstall apps you no longer use. Do not install battery 'booster' or 'cleaner' apps; they often use more power.

Why it helps: Stopping an app from running in the background is often enough to fix sudden drain.

06Turn down the screen and switch off what you don't useEasy

  1. Lower the screen brightness from Control Center on iPhone or the quick panel on Android.
  2. Turn off Bluetooth or Wi-Fi when you are not using them, from the same panel.
  3. Shorten the time before the screen locks itself.
  4. In places with very weak cell signal, turn on Airplane Mode with Wi-Fi on if you don't need calls, since searching for signal drains the battery.

Why it helps: The screen and radios searching for signal are among the biggest users of battery power.

07Check battery healthEasy

  1. On iPhone 15 or later: go to Settings > Battery > Battery Health. On iPhone 14 or earlier: Settings > Battery > Battery Health & Charging.
  2. On iPhone, look at the maximum capacity and for any message recommending battery service.
  3. On Android (Samsung): open the Samsung Members app, tap Support, tap Get Started under Phone diagnostics, and when the check finishes tap Battery status. The result is Normal, Weak or Bad.
  4. On Pixel 8a or later: go to Settings > Battery > Battery health. 'Reduced' means capacity is below 80% and a replacement is worth considering.
  5. If the battery shows as worn, the fix is a battery replacement by the maker or an authorized repair shop.

Why it helps: An aging battery holds less charge, and no setting can make up for that.

08Reset all settings on iPhone (keeps your data)AdvancedResets settings

  1. Try this only if nothing above helped and battery health looks normal.
  2. Back up your iPhone to iCloud or a computer first, just in case.
  3. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings.
  4. This keeps your photos, apps and messages but returns settings such as Wi-Fi passwords, wallpaper, privacy choices and Location Services to their defaults.
  5. Do not choose Erase All Content and Settings, which wipes the phone.

Why it helps: A setting changed by an update or an app can cause hidden drain, and a settings reset clears it without deleting your data.

Check it's fixed

  • The battery usage screen no longer shows one app with unusually high use.
  • The battery percentage drops only a little overnight with the screen off.
  • Over a normal day the phone lasts noticeably longer than before.

When to get help

If battery health shows the battery is worn or 'Reduced', the phone shuts down at 20-30%, or the back or screen is bulging, stop using it and get the battery replaced by Apple, Samsung, Google or an authorized repair shop. A swollen battery or a phone that gets very hot needs professional help right away.

Questions

Why is my battery draining fast after an update?

After a major update the phone often indexes photos, messages and other data in the background, which can drain the battery faster for a day or two. If it still drains fast after that, check the battery usage screen and update your apps.

Does closing apps save battery?

Not usually. Phones already manage apps in the background on their own. Only force stop or limit an app that the battery usage screen shows is using far more power than it should.

What battery health percentage means I need a new battery?

Around 80% of original capacity is the usual line: Pixel shows 'Reduced' below 80%, and Samsung Members shows 'Weak' or 'Bad'. On iPhone, check for a service message on the Battery Health screen.

Is it normal for my phone to get warm while the battery drains?

Slightly warm during heavy use or charging is normal. If it gets very hot, smells of burning or the case starts to bulge, stop using it and get it checked.

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