The biggest battery drains on your iPhone
Your iPhone battery drains fastest when the screen is on at full brightness, when apps run in the background, when location services are active, and when your phone searches for a weak cellular signal. These four things alone account for most of the battery loss you notice between charges. The screen uses more power than anything else — a bright display can drain 20 to 30 percent of your battery in an hour of active use.
Beyond the screen, background app refresh lets apps check for new information even when you are not using them. Location services drain battery because your phone is constantly calculating your position using GPS, cellular towers, or Wi-Fi networks. A weak signal forces your phone to work harder to stay connected, which uses significantly more power than a strong signal. Understanding which of these is draining your battery lets you make real choices about what to turn off and what to leave running.
Key Takeaways
- Screen brightness is the single largest battery drain; lowering it to 40 to 50 percent or turning on auto-brightness can extend battery life by several hours.
- Background app refresh drains battery by letting apps update in the background; turning it off for apps you do not check constantly saves 10 to 15 percent of daily battery use.
- Location services, especially GPS-based apps like maps and fitness trackers, drain battery quickly; turn them off for apps that do not need your real-time location.
- A weak cellular signal forces your phone to work harder and drains battery faster than a strong signal; moving to an area with better reception or switching to Wi-Fi saves power.
- Older iPhones and older batteries naturally drain faster because the battery chemistry degrades over time and cannot hold as much charge.
Screen brightness and display settings
Your screen is the biggest power consumer on your iPhone. At maximum brightness, it can drain 20 to 30 percent of your battery in one hour of continuous use. Lowering brightness to 40 to 50 percent cuts that drain roughly in half. The easiest way to reduce screen drain is to turn on auto-brightness, which adjusts the screen to match the light around you — this setting is in Settings > Display & Brightness > Auto-Brightness.
The type of display also matters. Older iPhones with LCD screens use less power at lower brightness levels but drain steadily at any brightness. Newer iPhones with OLED screens (iPhone 12 and later) use less power overall because they can turn off individual pixels, but they still drain faster at high brightness. If you are using an older iPhone, lowering brightness has a bigger effect on battery life than it does on newer models.
Turning off True Tone (which adjusts color temperature to match your surroundings) saves a small amount of battery, but the effect is minor — usually less than 2 percent of daily use. The bigger win is lowering brightness or turning on auto-brightness. If you spend most of your day indoors under artificial light, auto-brightness often keeps your screen dimmer than you would set it manually, which extends battery life without you having to think about it.
Background app refresh and notifications
Background app refresh lets apps check for new information even when you are not actively using them. Email apps check for new messages, news apps read headlines, and social media apps refresh feeds — all while your phone is locked or you are using a different app. This constant checking drains battery because it wakes up your phone's processor and radio repeatedly throughout the day.
You can turn off background app refresh entirely in Settings > General > Background App Refresh, or turn it off for individual apps. The most effective approach is to turn it off for apps you do not check constantly — news apps, social media, and games rarely need to refresh in the background. Keep it on for email, messaging, and calendar apps if you want notifications to arrive promptly. Turning off background refresh for five to ten apps typically saves 10 to 15 percent of your daily battery drain.
Push notifications also drain battery because they wake your phone and light up the screen. Turning off notifications for apps you do not need to hear from when ready (games, shopping apps, news alerts) saves power and reduces distractions. Go to Settings > Notifications and turn off notifications for individual apps, or turn off "Allow Notifications" entirely for apps that are not urgent.
Location services and GPS
Location services drain battery because your phone is constantly calculating where you are using GPS, cellular tower data, or Wi-Fi networks. GPS is the most power-hungry method — it uses your phone's radio and processor continuously. Apps like maps, fitness trackers, and weather apps use location services, and some apps request location even when they do not strictly need it.
You can turn off location services entirely in Settings > Privacy & Security > Location Services, but that disables features like Find My iPhone and emergency location sharing. A better approach is to turn off location for individual apps. Go to Settings > Privacy & Security > Location Services, scroll down, and change each app to "Never," "While Using," or "Always." Choose "While Using" for apps like maps that need your location only when you are actively using them. Choose "Never" for apps that do not need location at all — most games, shopping apps, and news apps work fine without it.
Fitness apps and running trackers drain battery fastest because they use GPS continuously while you exercise. If you use these apps regularly, expect 15 to 25 percent battery drain per hour of use. Turning off background location updates in the app's settings (not just in iOS settings) can reduce this drain slightly, but continuous GPS use will always drain battery quickly.
Cellular signal strength and network type
Your iPhone drains battery faster when it is searching for a strong cellular signal. In areas with weak signal (one or two bars), your phone works harder to stay connected, using more power than in areas with strong signal (three or four bars). This is because your phone's radio has to transmit at higher power to reach distant towers. If you spend most of your day in an area with weak signal — a basement, a rural location, or a building with poor reception — your battery will drain noticeably faster than someone in an area with strong signal.
Switching between cellular networks also drains battery. If your phone is constantly switching between 4G and 5G, or between cellular and Wi-Fi, it uses extra power. In areas where 5G signal is weak or spotty, turning off 5G in Settings > Cellular > Cellular Data Options > Voice & Data and choosing "LTE" instead can extend battery life. Wi-Fi uses less power than cellular, so connecting to Wi-Fi when it is available saves battery compared to using cellular data.
Airplane mode turns off all wireless radios and stops your phone from searching for signal, which is why battery drain is minimal in airplane mode. If you are in an area with no signal and do not need to receive calls or messages, turning on airplane mode prevents your phone from wasting power searching for a connection.
Battery age and health
Your iPhone battery naturally degrades over time. After 500 full charge cycles (roughly one year of normal use), a battery retains about 80 percent of its original capacity. After two years, it may retain only 60 to 70 percent. This is normal chemistry — lithium-ion batteries lose capacity as they age. An older battery drains faster because it cannot hold as much charge, not because something is wrong with your phone.
You can check your battery health in Settings > Battery > Battery Health & Charging. The "Maximum Capacity" percentage shows how much charge your battery can hold compared to when it was new. If it shows 80 percent or higher, your battery is in good condition. If it shows below 80 percent, your battery is aging and will drain faster than a new battery would. If it shows below 50 percent, consider replacing the battery — Apple offers battery replacement for a fee, and third-party repair shops offer it as well.
Older iPhone models (iPhone 8 and earlier) have smaller batteries than newer models, so they naturally drain faster even with a healthy battery. An iPhone 8 has a 1,821 mAh battery, while an iPhone 15 has a 3,349 mAh battery — nearly twice the capacity. If you are using an older iPhone, faster battery drain is expected, and upgrading to a newer model is the only way to significantly extend battery life.
Apps that drain battery quickly
Some apps drain battery much faster than others because of what they do. Video streaming apps (YouTube, Netflix, TikTok) drain battery quickly because they use the screen at full brightness and read data continuously. Gaming apps drain battery because they use the processor intensively and often use location services or push notifications. Navigation apps (Google Maps, Apple Maps) drain battery because they use GPS continuously and keep the screen on.
You can see which apps are using the most battery in Settings > Battery > 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 is using more than 10 to 15 percent of your daily battery and you do not use it heavily, it may be running in the background more than necessary. You can turn off background app refresh for that app, turn off its notifications, or turn off location services for it.
Social media apps and messaging apps drain battery because they refresh constantly and send notifications frequently. If you use these apps heavily, expect them to be in your top battery users. Turning off background refresh and notifications for these apps saves battery without preventing you from using them — you just will not see updates until you open the app.
Frequently Asked Questions
Does closing apps in the app switcher save battery?
No. Closing apps does not save battery because iOS suspends apps automatically when you switch away from them. Forcing them closed and reopening them actually uses more battery because your phone has to reload them from storage. Leave apps in the app switcher and let iOS manage them.
Does turning off Wi-Fi save battery?
No. Wi-Fi uses less power than cellular data, so turning off Wi-Fi and using cellular instead drains battery faster. Keep Wi-Fi on when it is available. Turning off Wi-Fi only saves battery if you are in an area with weak Wi-Fi signal and strong cellular signal, because your phone will stop searching for the weak Wi-Fi network.
Why does my battery drain faster in cold weather?
Cold temperatures slow down the chemical reactions inside your battery, which temporarily reduces its capacity. Your iPhone may show a lower battery percentage in cold weather, but the battery is not actually damaged. When the phone warms up, the battery percentage returns to normal. Extreme cold (below 32°F) can cause temporary shutdown, but this does not harm the battery.
Does low power mode really extend battery life?
Yes. Low Power Mode reduces screen brightness, limits background app refresh, disables some visual effects, and reduces processor speed. It typically extends battery life by 15 to 25 percent. You can turn it on manually in Settings > Battery > Low Power Mode, or set it to turn on automatically when your battery reaches 20 percent.
Can I improve battery life by restarting my iPhone?
Restarting can help if an app is stuck or using unusual amounts of battery, but it is not a regular fix. Restart your iPhone by holding the power button and volume button together until the power-off slider appears, then slide to power off. Wait 10 seconds and turn it back on. If battery drain returns to normal, an app was the problem. If it does not improve, the issue is likely battery age or a hardware problem.