The most common battery drains on iPhone

Your iPhone battery drains fastest because of screen brightness, background app activity, location services running constantly, and push notifications. These four things account for most of the battery loss people notice between charges. The screen alone can drain 20 to 40 percent of your battery in a day if it stays at full brightness, especially on newer models with larger displays.

After those four, the next culprits are older apps that haven't been updated in months, Bluetooth left on when you're not using it, and mail or calendar apps checking for new messages every few minutes. If your phone is warm to the touch, something in the background is working hard — usually location services, video playback, or an app syncing data.

Key Takeaways

  • Screen brightness is the single largest battery drain on most iPhones, and lowering it to 30 to 40 percent cuts battery loss by a quarter or more.
  • You can see exactly which apps are using the most battery by opening Settings > Battery > Battery Usage, which shows the percentage each app consumed in the last 24 hours or 10 days.
  • Background App Refresh lets apps run and check for updates even when you're not using them; turning it off for apps you don't need constant updates from saves 5 to 15 percent battery per day.
  • Location services drain battery fastest when set to "Always" instead of "While Using"; changing apps from Always to While Using or Never can add two to four hours to your battery life.
  • If your battery drains in a few hours instead of a full day, a hardware problem or a single misbehaving app is usually the cause, and Battery Usage will show which app is responsible.

How to check which apps are draining your battery

Open Settings, then tap Battery, then tap Battery Usage. You will see a list of every app on your phone ranked by how much battery it used in the last 24 hours. The percentage next to each app name is what portion of your total battery that app consumed. If one app is using 30 percent or more while you barely use it, that app is the problem.

Scroll down to see the full list — sometimes the worst offenders are apps you forgot you had. If you see an app using 15 percent or more and you don't use it daily, uninstall it or turn off its background activity. You can also tap the clock icon next to "Last 24 Hours" to see the last 10 days instead, which shows you whether the drain is a one-time spike or a pattern.

If an app shows high battery use but you were actively using it — like Maps while driving or YouTube while watching — that's normal and not a problem. The issue is apps using battery when you're not touching your phone.

Screen brightness and display settings

Your screen is almost always the largest battery drain. On iPhone 14 and newer models with always-on displays, the screen can use 30 to 40 percent of your daily battery. Lowering brightness from 100 percent to 40 percent typically adds three to five hours to your battery life.

Turn on Auto-Brightness by going to Settings > Accessibility > Display & Text Size > Auto-Brightness. This adjusts your screen brightness based on the light around you, so you're not running full brightness indoors or in dim rooms. You can also enable Low Power Mode, which reduces screen refresh rate, limits background activity, and dims the display — this alone can extend battery life by a full day when your phone is below 20 percent.

If you have an iPhone 13 Pro, 14 Pro, or 15 Pro, the always-on lock screen display is a significant drain. You can turn it off in Settings > Display & Brightness > Lock Screen, or set it to show only when you're looking at your phone by enabling Attention Aware Features in Settings > Face ID & Passcode.

Background app activity and location services

Background App Refresh lets apps check for new messages, updates, or data even when you're not using them. This is useful for Mail, Messages, and Weather, but unnecessary for games, social media, or news apps. Turn it off selectively by going to Settings > General > Background App Refresh, then toggle off the apps you don't need constant updates from.

Location services drain battery because your phone is constantly using GPS, Bluetooth, or cellular triangulation to pinpoint your location. Many apps request location permission and then use it constantly even when you're not actively using the app. Go to Settings > Privacy & Security > Location Services, then tap each app and change it from "Always" to "While Using" or "Never". Maps, Weather, and Find My should stay on Always if you use them regularly, but most other apps only need location while you're actively using them.

If you don't use location-based reminders or Find My Friends, you can turn off Location Services entirely in Settings > Privacy & Security > Location Services. This can add four to six hours to your battery life, though some features like emergency location sharing will stop working.

Mail, calendar, and notification settings

Mail and Calendar apps drain battery by checking for new messages and events on a schedule you set. By default, Mail checks every 15 minutes, which means your phone wakes up, connects to the internet, and downloads data 96 times per day. Change this by going to Settings > Mail > Accounts > Fetch New Data, then set it to Hourly or Manually instead of Every 15 Minutes.

Push notifications also drain battery because they wake your screen and trigger background activity. You don't need notifications from every app. Go to Settings > Notifications and turn off notifications for apps that don't need to alert you — games, shopping apps, and news apps are good candidates. Keep notifications on for Messages, Mail, Calendar, and Phone so you don't miss important contacts.

Bluetooth, Wi-Fi, and cellular settings

Bluetooth drains battery when it's on but not connected to a device, because your phone is constantly scanning for nearby devices. Turn it off in Settings > Bluetooth when you're not using wireless headphones, speakers, or a smartwatch. The same applies to Wi-Fi — if you're not connected to a network, turn Wi-Fi off in Settings > Wi-Fi instead of leaving it scanning for networks.

Cellular signal strength also affects battery drain. If you're in an area with weak signal, your phone works harder to maintain a connection, which drains battery faster. If you're in a place with no signal at all, enable Airplane Mode in Settings > Airplane Mode to stop your phone from searching for a signal.

When battery drain means a hardware problem

If your battery drains from 100 to 0 percent in two to four hours with normal use, or if Battery Usage shows no single app using more than 15 percent, the problem is likely hardware rather than software. This can mean the battery itself is degraded, the charging port is damaged, or a component inside the phone is failing.

Check your battery health by going to Settings > Battery > Battery Health & Charging. If Maximum Capacity is below 80 percent, your battery has degraded and will drain faster than normal — this is expected after two to three years of daily use, but if your phone is newer than a year old and capacity is below 90 percent, a hardware defect may be responsible. If Maximum Capacity is above 80 percent but battery still drains in a few hours, contact Apple Support or visit an Apple Store to have the phone diagnosed.

Frequently Asked Questions

Why does my iPhone battery drain so fast overnight?

Overnight drain is usually caused by Background App Refresh, mail checking, or location services running while your phone is locked. Turn off Background App Refresh for apps you don't need updates from, set Mail to check hourly instead of every 15 minutes, and change location services to "While Using" for most apps. If drain is more than 5 to 10 percent overnight, check Battery Usage to see which app is responsible.

Does closing apps in the background save battery?

No. Closing apps by swiping them away from the app switcher does not save battery — in fact, it can use more battery because your phone has to reload the app from scratch the next time you open it. Instead, turn off Background App Refresh for apps you don't need constant updates from, which actually stops them from running in the background.

Is it bad to use Low Power Mode all the time?

Low Power Mode reduces performance and limits some features like mail fetching and automatic downloads, but it's not harmful to your phone. You can use it whenever you want. Many people keep it on below 50 percent battery to extend the day, then turn it off when they charge. There's no damage to your battery or hardware from using it constantly.

Can a single app drain my battery that fast?

Yes. If Battery Usage shows one app using 40 percent or more of your battery and you barely use it, that app is the problem. Uninstall it or check if it has a newer version in the App Store — outdated apps often have bugs that cause high battery drain. If the app is essential, contact the developer to report the issue.

Does turning off 5G save battery?

Yes, but only slightly. 5G uses more power than 4G LTE, but the difference is usually 5 to 10 percent per day. Turn it off in Settings > Cellular > Cellular Data Options > Voice & Data, then select LTE if you want to save battery. However, 5G is faster for downloads and uploads, so the trade-off depends on whether you need the speed more than the battery life.