iPhone Battery Health: When Is It Time for a New Battery?
Updated November 6, 2026
Every phone battery wears down with use. The question is not if, but when the drop starts getting in your way: the phone dies by mid-afternoon, shuts off in the cold, or slows down when you open the camera.
Your iPhone tells you a lot about its own battery. Here is where to look and how to read it before you spend money on a new phone.
- Step 1Open Battery HealthGo to Settings › Battery › Battery Health (on newer iOS: Battery Health & Charging). Look at Maximum Capacity.
- Step 2Check the cycle countOn iPhone 15 and newer, Settings › General › About shows how many full charge cycles the battery has done.
- Step 3Look for a service messageIf Battery Health says “Service” or recommends a replacement, iOS has measured real wear.
- Step 4Notice how it behavesSudden shutdowns at 20–30%, a phone that only lives on the charger, or heat while charging are all signs.
What the 80% line means
Maximum Capacity compares today’s battery with the day it was new. Apple designs iPhone batteries to keep about 80% of their original capacity after 500 full cycles on iPhone 14 and earlier, and after 1,000 cycles on iPhone 15 and newer.
Below 80% most people feel it every day. Above 80% a new battery can still help if you use the phone hard (navigation, video, hotspot), but it is less urgent.
Signs you should not wait
A swollen battery pushes the screen or back glass up, so you may see a gap at the edge or the screen lifting. Stop charging the phone and bring it in: a swollen lithium battery should be replaced, not used.
Random restarts and the phone shutting off with charge left also point to a battery that can no longer deliver steady power.
Genuine Apple or not: what you will see
On many recent iPhones, iOS shows a message in Battery settings when the battery is not a genuine Apple part. The phone keeps working normally; some health readings may not show. We tell you which battery you are getting before we start.
Questions
How long does an iPhone battery replacement take?
On most iPhones it is a while-you-wait job. Bigger or older models can take longer; the store tells you the ready time when you drop it off.
Will I lose my photos or apps?
A battery replacement does not touch what is stored on the phone. A fresh backup before any repair is still a good habit.
Is it worth it for an older iPhone?
Often, yes. A new battery costs far less than a new phone and can make an older iPhone feel usable again, as long as the rest of the phone is in good shape.