The most common reasons your iPhone battery empties quickly
iPhone batteries drain fastest when your screen brightness is set high, when background app refresh is turned on for apps you do not use, or when location services run constantly. A battery that worked fine for years may suddenly drain in hours because the battery itself has worn out — lithium batteries lose capacity after 500 full charge cycles, and most iPhones hit that point after two to three years of daily use.
The second most common cause is a single app consuming power in the background. Mail, Maps, Spotify, and social media apps often refresh without you opening them. If your battery drains only when you use one specific app, that app is the problem. If it drains even when your phone is locked and you are not using it, the culprit is usually background refresh, location services, or a worn battery.
iOS updates can also cause temporary drain spikes. After you update to a new iOS version, your phone indexes files and rebuilds caches for 24 to 48 hours, which uses extra power. This is normal and stops on its own.
Key Takeaways
- Screen brightness above 50 percent and background app refresh are the fastest ways to drain a battery; turning both down extends your day by hours.
- Check Settings > Battery to see which apps used the most power in the last 24 hours, and turn off background refresh for apps you do not need to update constantly.
- If your iPhone is more than two years old, the battery itself may have lost 20 percent of its capacity, and Apple can replace it for $69 to $99 depending on your model.
- Location services, Bluetooth, and Wi-Fi searching all consume power; turn off location for apps that do not need it and disable Wi-Fi scanning when you are not moving.
How to check which apps are using the most battery
Open Settings, tap Battery, then tap Battery Usage. You will see a list of every app and the percentage of your battery it used in the last 24 hours. Apps at the top of the list are draining your power the fastest. If one app is using more than 20 percent of your battery and you do not use it heavily, that app is the problem.
Tap the app name to see whether it used power while running in the foreground (you were using it) or in the background (it was running without you opening it). If an app like Mail or Spotify shows high background usage, turn off background app refresh for that app. If it shows high foreground usage, the app itself is power-hungry — you can delete it, use a lighter alternative, or accept that it drains your battery faster.
Check this list once a week if your battery is draining unusually fast. A new app you installed last week often shows up here first, which tells you when ready whether it is the cause.
Turn off background app refresh and location services
Background app refresh lets apps update their content even when you are not using them. This is useful for Mail and Messages but wasteful for games, news apps, and social media. Open Settings, tap General, then Background App Refresh. You will see a list of every app with a toggle switch next to it. Turn off the toggle for any app that does not need to update while you are away from it.
Location services drain battery because your phone is constantly using GPS, Bluetooth, or cellular triangulation to figure out where you are. Open Settings, tap Privacy & Security, then Location Services. You will see a list of apps with location permission. For each app, tap it and choose "Never" or "While Using" instead of "Always." Maps and weather apps need "Always" to work properly, but most other apps do not.
If you turn off location services entirely, some apps will not work — Maps will not give you directions, and Find My will not locate your phone. Instead, turn off location only for the apps that do not need it. This single change often saves 10 to 15 percent of your daily battery use.
Lower your screen brightness and enable auto-brightness
Your screen is the single largest power consumer on your iPhone. If you keep brightness above 75 percent, your battery will drain 30 to 40 percent faster than it would at 40 percent brightness. Open Settings, tap Display & Brightness, and move the brightness slider down to 40 or 50 percent. You will adjust to the lower brightness within a day.
Enable auto-brightness so your phone adjusts brightness based on the light around you. In the same Display & Brightness menu, toggle on Auto-Brightness. Your phone will dim in dim rooms and brighten in sunlight, which uses less power than keeping brightness constant.
If you spend most of your day indoors under artificial light, keeping brightness at 30 to 40 percent is comfortable and saves significant battery. If you work outdoors, auto-brightness will keep your screen readable without draining power unnecessarily.
Disable Wi-Fi and Bluetooth scanning when you do not need them
Your iPhone constantly scans for Wi-Fi networks and Bluetooth devices even when you have Wi-Fi and Bluetooth turned off. This scanning uses power. If you are not moving and you are not expecting to connect to a new device, you can reduce this drain. Open Settings, tap Privacy & Security, then Location Services. Scroll down and toggle off Wi-Fi Networking. This stops your phone from scanning for Wi-Fi networks in the background.
Bluetooth scanning is harder to disable completely, but you can turn off Bluetooth entirely when you are not using wireless headphones or a car connection. Swipe down from the top right corner to open Control Center, then tap the Bluetooth icon to turn it off. Turn it back on only when you need it.
These changes save 5 to 10 percent of battery per day if you are stationary. If you move around frequently, the power saved is smaller because your phone needs to scan to stay connected.
Check whether your battery health has degraded
Open Settings, tap Battery, then Battery Health & Charging. You will see a number called Maximum Capacity, which shows what percentage of the battery's original capacity remains. A new iPhone shows 100 percent. After two years of daily use, most iPhones show 80 to 85 percent. After three years, 75 to 80 percent is normal.
If your Maximum Capacity is below 80 percent and your battery drains in a few hours, the battery itself is worn out and needs replacement. Apple charges $69 to $99 to replace an iPhone battery depending on your model. You can also visit an Apple Store or authorized repair shop to have it replaced.
If your Maximum Capacity is above 85 percent but your battery still drains fast, the problem is not the battery itself — it is one of the settings or apps listed above. Focus on turning off background refresh and lowering brightness first.
Restart your iPhone and update to the latest iOS version
A restart clears temporary files and stops apps that are stuck running in the background. Hold down the power button and either volume button until the power-off slider appears. Drag it to turn off your phone, wait 30 seconds, then press the power button again to turn it back on. Check your battery drain after a restart — it often improves when ready.
Open Settings, tap General, then Software Update to check whether a new iOS version is available. Install it if one exists. iOS updates sometimes fix battery drain bugs, though the first 24 to 48 hours after an update may show higher drain while your phone rebuilds its cache. This is temporary.
If drain is still high after a restart and an update, the problem is almost certainly one of the apps or settings described above. Go back to Battery Usage in Settings and turn off background refresh for the top three apps.
Frequently Asked Questions
Does using Low Power Mode actually save battery?
Yes. Low Power Mode reduces performance and background activity, which extends your battery by 15 to 25 percent. Open Settings, tap Battery, and toggle on Low Power Mode. Your phone will run slower and some features like automatic downloads will pause, but it will last much longer. Turn it off when you plug in to charge.
Why does my battery drain faster in cold weather?
Lithium batteries work slower in cold temperatures, so your phone drains faster and may shut down at 20 percent battery even though it shows charge remaining. This is temporary — the battery recovers when it warms up. Keep your phone in a pocket or bag in cold weather to slow the drain.
Can I stop apps from running in the background without turning off background app refresh?
Not completely. You can force-close an app by swiping up from the bottom of the screen and holding on the app preview, then swiping up to close it. But it will reopen the next time you use it. The only permanent way to stop an app from running in the background is to turn off background app refresh for that app or delete it.
Does leaving my phone plugged in overnight damage the battery?
No. Modern iPhones stop charging at 100 percent and hold the charge without draining, so leaving your phone plugged in overnight does not harm the battery. However, keeping your phone plugged in constantly at 100 percent for months can slightly reduce long-term battery health. Unplugging it once it reaches 100 percent is ideal but not necessary.
What should I do if my battery drains even when my phone is completely off?
A completely powered-off iPhone should not drain battery for weeks. If it does, the battery itself may be failing or there may be a hardware problem. Take your phone to an Apple Store or authorized repair shop to have it tested. They can tell you whether the battery needs replacement or whether there is a deeper issue.