The apps and settings that use the most power

Your iPhone battery drains fastest when apps run in the background, your screen brightness is high, location services are on, and your phone is searching for a weak cellular signal. A single app left refreshing in the background can drop your battery 5 to 15 percent in an hour. The screen itself — especially on newer iPhones with larger displays — uses more power than any other single component, which is why brightness matters more than almost anything else you can control.

Not all drain is equal. Some apps drain battery because they genuinely need to work in the background, like Maps tracking your route or a music app playing a song. Others drain it because they are poorly written or because you have given them permission to do something you did not realize. The difference between a phone that lasts all day and one that dies by noon often comes down to three or four specific settings or apps, not dozens of small leaks.

Key Takeaways

  • Screen brightness is the single largest battery drain on most iPhones; setting it to auto-adjust or keeping it below 40 percent extends battery life by several hours.
  • Location services, background app refresh, and Bluetooth drain significant power even when you are not actively using them; turning these off for apps that do not need them saves 10 to 20 percent of daily battery.
  • Apps that sync data constantly — email, social media, weather — drain more battery than apps you open and close; checking your battery usage in Settings shows which apps are the worst offenders.
  • A weak cellular signal forces your phone to work harder to stay connected; being in a basement or far from a tower can drain 20 to 30 percent more battery than normal.
  • Older iPhones and phones with degraded batteries drain faster because the battery itself holds less charge; Apple's Battery Health tool in Settings shows whether your battery is the problem.

Screen brightness and display settings

Your screen uses between 15 and 40 percent of your battery depending on how bright you keep it and how much time you spend looking at it. The newer the iPhone, the larger the screen, and the higher the brightness, the more power it draws. Setting brightness to 30 or 40 percent instead of maximum can add two to four hours to your battery life on a single charge.

Auto-brightness is the easiest fix. Go to Settings, then Display & Brightness, and turn on Auto-Brightness. Your phone will dim the screen in low light and brighten it in sunlight, which matches what you actually need to see without wasting power on brightness you do not use. If you spend most of your time indoors, a manual brightness setting around 30 to 40 percent is usually enough and saves more battery than auto-brightness alone.

Dark Mode also reduces battery drain, but only on iPhones with OLED screens — iPhone 12 and newer. On older iPhones with LCD screens, Dark Mode makes almost no difference. If you have an iPhone 12 or later, turning on Dark Mode in Settings, then Display & Brightness saves 5 to 10 percent of battery on a full day of use.

Background app refresh and location services

Background App Refresh lets apps update their content even when you are not using them. Mail can check for new messages, weather can update the forecast, and news apps can refresh headlines. This is convenient, but it drains battery constantly. Turning it off for apps that do not need it — games, social media, shopping apps — can save 10 to 15 percent of your daily battery.

To control it, go to Settings, then General, then Background App Refresh. You can turn it off entirely, or turn it off for individual apps. Keep it on for Mail, Messages, and any app you actually want to notify you of updates. Turn it off for everything else. The difference is noticeable within a day.

Location Services is a separate drain. Apps use GPS, Bluetooth, and cellular data to figure out where you are. GPS is the most power-hungry — it can drain 5 to 10 percent of your battery per hour if an app is using it constantly. Go to Settings, then Privacy, then Location Services. Turn it off entirely if you do not need it, or set individual apps to "While Using" instead of "Always." This means the app can only see your location when you have it open, not in the background.

Email, messaging, and data sync

Email is one of the worst battery drains because it syncs constantly. If you have Mail set to fetch new messages every 15 minutes, your phone checks the server 96 times a day. Each check uses power even if there are no new messages. Changing this setting can save 5 to 10 percent of your battery.

Go to Settings, then Mail, then Accounts, then Fetch New Data. Change the default from "Every 15 Minutes" or "Every 30 Minutes" to "Hourly" or "Manually." If you do not need when ready notifications, hourly is a good middle ground. For accounts you check rarely, set it to manual — your phone will only fetch mail when you open the Mail app.

Messaging apps like WhatsApp, Telegram, and iMessage also drain battery if they are syncing photos, videos, or location data in the background. Check Settings, then Privacy, then Location Services, and set these apps to "While Using" instead of "Always." The same applies to social media apps — they do not need your location when you are not using them.

Bluetooth, Wi-Fi, and cellular signal

Bluetooth drains battery when it is on, even if you are not connected to anything. If you have Bluetooth on but no headphones paired, your phone is still searching for devices. Turn it off when you are not using wireless headphones or speakers. Go to Settings, then Bluetooth, and toggle it off. The drain is small — usually 2 to 5 percent per day — but it adds up.

Wi-Fi uses less power than cellular data, so leaving Wi-Fi on when you are home saves battery compared to using 4G or 5G. However, if you are moving between locations and your phone is constantly searching for Wi-Fi networks, it drains battery faster than staying on cellular. If you are out and about, turn off Wi-Fi. If you are home or at work, leave it on.

Cellular signal is the biggest variable. When your phone has a weak signal — one or two bars — it works harder to stay connected and drains 20 to 30 percent more battery than when you have a strong signal. Being in a basement, a car, or far from a cell tower forces your phone to use more power. If you are in a weak signal area and do not need your phone, turning on Airplane Mode stops this drain entirely.

Apps that run constantly in the background

Some apps are designed to run in the background — Maps, music players, fitness trackers, and navigation apps need to keep working even when you are not looking at them. Others should not be running in the background at all. Games, social media, and shopping apps drain battery if they are refreshing content or tracking your location when you are not using them.

To see which apps are using the most battery, go to Settings, then Battery, then Battery Usage. This shows you the percentage of battery each app has used in the last 24 hours or the last 10 days. If an app you rarely use is in the top five, it is probably running in the background unnecessarily. Uninstall it, or go to Settings, then General, then Background App Refresh, and turn it off for that app.

Some apps also use a lot of battery because they are poorly optimized or have a bug. If an app is using 10 percent or more of your battery and you do not use it constantly, try uninstalling and reinstalling it. If the drain continues, delete the app. There is almost always an alternative that does the same thing without draining your battery.

Battery health and age

If your iPhone is more than two or three years old, the battery itself may be the problem. Lithium batteries degrade over time and hold less charge with each cycle. An iPhone battery is designed to retain 80 percent of its capacity after 500 full charge cycles. After 1,000 cycles — roughly two to three years of normal use — it may hold only 70 to 75 percent of its original capacity.

To check your battery health, go to Settings, then Battery, then Battery Health & Charging. This shows you the maximum capacity of your battery as a percentage. If it is below 80 percent, your battery is degraded. If it is below 70 percent, your phone will drain noticeably faster than it did when it was new. If it is below 50 percent, Apple recommends replacing the battery.

Battery replacement is available at Apple Stores and authorized repair shops. The cost varies by iPhone model, but it is usually between $50 and $100. A new battery will restore your phone to nearly full battery life, often extending it by four to six hours on a single charge compared to a degraded battery.

Frequently Asked Questions

Does closing apps in the background actually save battery?

No. Closing apps by swiping them away from the app switcher does not save battery on modern iPhones. iOS automatically manages app memory and suspends apps that are not in use. Manually closing apps forces your phone to reload them from scratch the next time you open them, which actually uses more battery. The only exception is if an app is visibly draining battery in Settings — then uninstalling it is better than closing it repeatedly.

Does turning off 5G save battery?

Yes, but not by much. 5G uses slightly more power than 4G LTE, but the difference is usually 5 to 10 percent of your daily battery. If you are in an area with poor 5G coverage, turning it off can help because your phone will not waste power searching for a 5G signal. Go to Settings, then Cellular, then Cellular Data Options, then Voice & Data, and select LTE instead of 5G Auto.

Why does my battery drain faster in cold weather?

Cold temperatures reduce the chemical reaction inside the battery, which temporarily reduces the amount of power it can deliver. Your battery is not damaged, but it will drain faster and may shut down at 20 or 30 percent instead of 0 percent. Warming your phone up — putting it in a pocket or holding it in your hand — restores normal battery performance. If your phone shuts down in the cold, this is normal and not a sign of a bad battery.

Can I use Low Power Mode all the time?

Yes. Low Power Mode reduces performance and background activity to extend battery life by 15 to 25 percent. It slows down app performance slightly and disables some features like automatic downloads and mail fetch. If you do not mind the slight slowdown, leaving Low Power Mode on all the time is a safe way to extend your battery life. Go to Settings, then Battery, then Low Power Mode, and toggle it on.

Does leaving my phone plugged in overnight damage the battery?

No. Modern iPhones have smart charging that stops charging at 100 percent and maintains the battery at that level. Leaving your phone plugged in overnight does not degrade the battery faster than normal use. However, keeping your battery between 20 and 80 percent most of the time does extend its lifespan. If you want to maximize battery longevity, unplug your phone when it reaches 100 percent and charge it again when it drops to 20 percent.