iPhone battery draining fast? 10 fixes that make it last longer

Battery drain has two very different causes: something on the phone is using too much power, or the battery can no longer hold a full charge. The fixes are completely different, so spend one minute working out which one you have before you change any settings.

Battery or software? Check this first

Open Settings › Battery › Battery Health. On iPhone 14 and older the menu is called Battery Health & Charging. Look at Maximum Capacity. If it is 80 percent or lower, or the screen says Service, the battery itself is worn and no setting will bring the lost hours back. A battery replacement will. If it is above 80 percent, the drain is almost always an app, a setting or a recent update, and the fixes below will help.

On iPhone 15 and later you will also see the cycle count on the same screen. A battery is designed to keep about 80 percent of its capacity for 1,000 cycles on these models, and 500 cycles on older ones, so a high count with a low percentage confirms the battery is simply old.

Why is my iPhone battery draining so fast all of a sudden?

When the drain starts suddenly, something changed. The most common triggers are:

• A new iOS version. After updating to iOS 27 or any major release, the phone spends a few days indexing and analyzing data in the background. Apple shows an Ongoing iOS Update note in Settings › Battery while this runs.
• One misbehaving app. A buggy update can keep an app awake in the background, using location or the processor nonstop.
• A weak signal. In a basement, a rural area or a crowded venue, the modem keeps boosting power to hold a connection.
• Heat. A hot phone, whether from the sun, a car dashboard or gaming, loses charge faster and ages the battery.
• A new phone setup. Restoring from a backup downloads every app and photo again, which can take a day or two. Settings may show Ongoing Device Setup.

How to read the Battery screen in iOS 26 and iOS 27

Since iOS 26, the Battery screen opens with a Daily Usage chart that compares today with your average over the last seven days. It tells you if you are using more, the same or less than usual. Tap View All Battery Usage to see each app. Apps that used far more than normal are highlighted, with a note explaining why: longer on screen, longer in the background, or more notifications than usual.

Pay attention to background time. An app you barely opened but that shows hours of background activity is the one to deal with. High on-screen use, on the other hand, just means you used that app a lot, and the only fix is using it less or lowering brightness. The top of the screen may also show Suggestions, such as turning on Auto-Brightness or Auto-Lock, based on how you use the phone.

Still draining? Try these next

Is it worth replacing the battery?

Usually yes, if the rest of the phone still does what you need. A new battery restores the original battery life and can remove slowdowns caused by peak performance management on older iPhones. Apple's out-of-warranty price is $69 to $129 depending on the model, and it is free if you have AppleCare+ and the battery is below 80 percent. Authorized repair shops use the same genuine parts.

It makes less sense on a phone that no longer gets iOS updates, has a cracked screen as well, or is so slow that you already want a new one. In that case, compare the repair cost with its trade-in value before you pay for a new battery.