The most common reason: apps running in the background
Your iPhone battery drains fastest when apps keep working even after you close them. Unlike a desktop computer, your phone doesn't stop an app completely when you swipe it away—it pauses the app and leaves it in memory, ready to resume. Some apps are designed to keep running in the background: music players, navigation apps, fitness trackers, and messaging services all need to stay active to work properly. But many apps request background activity permission and then use it to check for updates, load ads, or track your location even when you're not using them.
The second culprit is screen brightness and screen-on time. Your display uses more power than any other component in the phone. If you're using your phone for six hours straight, or if your brightness is set to maximum, the battery will drain noticeably faster than on a day when you check it briefly every few minutes.
Key Takeaways
- Check Settings > Battery to see which apps used the most power in the last 24 hours or the last 10 days, and disable background activity for apps you don't need running constantly.
- Reduce screen brightness or enable Auto-Brightness in Settings > Display & Brightness to cut power use significantly.
- Turn off location services for apps that don't need it, because GPS drains the battery much faster than cellular or Wi-Fi.
- Check Settings > Privacy > Location Services to see which apps have permission to track your location at all times.
- If battery drain started suddenly after an iOS update, restart your phone—sometimes background processes take time to settle and use extra power temporarily.
How to see which apps are draining your battery
Open Settings, then tap Battery. You'll see two options: "Last 24 Hours" and "Last 10 Days." Tap the timeframe you want to check. Below that, you'll see a list of apps ranked by how much battery they used, with a percentage next to each one. The percentages add up to 100 percent of the power your phone used in that period.
Look for apps that seem high on the list but you don't use often. For example, if a social media app you opened once shows 18 percent battery use, that app is doing something in the background. If your email app shows 25 percent, it's checking for new messages frequently. This list tells you which apps to investigate next.
Tap any app in the list to see more detail. You'll see whether the app was running in the foreground (while you were actively using it) or in the background. If an app shows high background activity, that's where the drain is coming from.
Turn off background app refresh for apps you don't need
Go to Settings > General > Background App Refresh. You'll see a toggle at the top to turn off background refresh entirely, or you can scroll down and turn it off for individual apps. If you turn off the master toggle, all apps stop running in the background—but your phone won't get notifications from messaging apps, and music apps won't play. A better approach is to leave the master toggle on and turn off background refresh only for apps that don't need it.
For example, you probably don't need a news app, a game, or a weather app to refresh in the background. You can turn those off. But keep background refresh on for Mail, Messages, phone calls, and any app that needs to alert you to something urgent. After you change these settings, check your battery usage again in a day or two to see if the drain has slowed.
Disable location services for apps that don't need it
GPS uses significantly more power than cellular or Wi-Fi data. Go to Settings > Privacy > Location Services. You'll see a list of every app that has asked for permission to know your location. Tap each app and choose "Never," "While Using," or "Always." Choose "Never" for apps that don't need your location—games, note-taking apps, and most social media apps fall into this category. Choose "While Using" for maps and navigation apps so they only use GPS when you're actively using them. Reserve "Always" for apps like Find My iPhone or a fitness app that genuinely needs to track you in the background.
Pay special attention to apps set to "Always." These are the biggest battery drain because they keep GPS active even when you're not using the app. If you see an app you don't recognize with "Always" permission, change it to "Never."
Reduce screen brightness and enable auto-brightness
Your screen is the single largest power consumer on your phone. Go to Settings > Display & Brightness and turn on "Auto-Brightness." This setting adjusts your screen brightness based on the light in the room, so you're not running maximum brightness indoors or in dim light. You can also manually drag the brightness slider down to a comfortable level—most people don't need brightness above 40 or 50 percent for everyday use.
If you use your phone heavily throughout the day, reducing brightness by just 20 percent can extend your battery life by an hour or more. Test this for a few days to find the balance between visibility and battery life that works for you.
Check for battery health and recent iOS updates
Go to Settings > Battery > Battery Health & Charging. You'll see a number labeled "Maximum Capacity"—this is the percentage of the battery's original capacity that remains. If your phone is a year old and shows 90 percent, that's normal. If it shows 70 percent or lower, the battery itself is degrading and will drain faster than it used to. Apple's battery replacement program costs money, but if your phone is still under warranty or covered by AppleCare+, replacement may be covered.
If your battery started draining noticeably faster right after you updated iOS, restart your phone. Sometimes background processes take time to settle after an update, and your phone may be indexing files or running maintenance tasks that use extra power temporarily. Wait a day or two and check again—the drain usually returns to normal once these tasks finish.
Turn off features you're not using
Bluetooth, Wi-Fi, and cellular data all use power. If you're not using Bluetooth headphones, turn off Bluetooth in Control Center. If you're in an area with weak cellular signal, your phone works harder to maintain a connection—in this case, turning on Airplane Mode and using Wi-Fi instead can actually save battery. Similarly, if you don't need location services, Wi-Fi, or Bluetooth, turning them off when you're not using them helps.
Enable Low Power Mode in Settings > Battery when your battery drops below 20 percent. This mode reduces background activity, limits performance, and turns off some visual effects. Your phone will run slower, but it will last significantly longer. Some people turn on Low Power Mode at 30 or 40 percent if they know they won't be near a charger for several hours.
Frequently Asked Questions
Why does my battery drain faster in cold weather?
Cold temperatures slow down the chemical reactions inside your battery, so it can't deliver power as quickly. Your phone may shut down at 20 percent battery even though the battery isn't actually empty—it just can't function in the cold. Warm your phone up indoors and the battery percentage will return to normal. This is temporary and doesn't mean your battery is damaged.
Does closing apps in the app switcher save battery?
No. Closing an app by swiping it away in the app switcher doesn't save battery—in fact, it can use more power because your phone has to reload the app from scratch the next time you open it. Let iOS manage your apps. Only close an app if it's frozen or behaving strangely.
Should I turn off Wi-Fi to save battery?
No. Wi-Fi uses less power than cellular data, so leaving Wi-Fi on actually saves battery when you're connected to a network. Turn off Wi-Fi only if you're in an area with no Wi-Fi networks and you're not using data.
Can a full charge damage my battery?
Modern iPhones are designed to handle being plugged in all night. Your phone stops charging at 100 percent and maintains that level, so leaving it plugged in overnight won't harm the battery. However, keeping your battery between 20 and 80 percent most of the time does extend the overall lifespan of the battery over years of use.
Why does my battery drain faster after I update iOS?
After an iOS update, your phone runs background processes like indexing files and optimizing performance. This can take several hours to a few days. Restart your phone to speed up these processes, and the battery drain should return to normal. If it doesn't improve after two days, check the Battery section again to see if a specific app is now using more power.