Where to find your battery health on iPhone
Your iPhone stores a battery health report in Settings, and you can read it in under a minute. Open Settings, tap Battery, then Battery Health & Charging. You will see a percentage — that number tells you how much capacity your battery holds compared to when it was new.
The percentage appears next to "Maximum Capacity". A new iPhone shows 100%. As you charge and use the phone, this number drops. At 80%, your battery is considered degraded but still functional. Most people notice slower performance or shorter runtime somewhere between 70% and 80%.
Below Maximum Capacity, you will also see "Peak Performance Capability". This line tells you whether iOS has slowed your phone to protect the battery. If it says your iPhone is operating at normal performance, no throttling is happening. If it says your phone has been slowed, that is iOS managing power to prevent unexpected shutdowns.
Key Takeaways
- Battery health appears as a percentage in Settings > Battery > Battery Health & Charging, showing how much capacity remains compared to a new battery.
- A battery below 80% capacity is considered degraded, and you may notice shorter runtime or slower performance.
- Peak Performance Capability tells you whether iOS has slowed your phone to prevent shutdowns caused by battery wear.
- If your battery is below 50%, Apple will replace it for a fee, or free if your phone is under warranty or covered by AppleCare+.
What the percentage actually means
The number you see is not a prediction of how long your battery will last. It is a snapshot of how much charge your battery can hold right now, measured against its original capacity. A battery at 85% can still power your phone for a full day if you use it lightly, or a few hours if you use it heavily.
Apple designs iPhone batteries to retain 80% of their capacity after 500 full charge cycles. A charge cycle means draining the battery completely and charging it back to 100%, though it does not have to happen in one day. If you charge your phone from 50% to 100%, that counts as half a cycle.
The health percentage drops faster if you expose your phone to heat, charge it constantly, or let it drain to zero repeatedly. It also drops naturally over time, even if you treat the phone carefully. There is no way to stop this process, only to slow it.
When your battery health triggers performance slowdown
iOS automatically slows your phone when the battery can no longer deliver the power the processor demands. This happens to prevent unexpected shutdowns — if your battery is worn, it cannot supply enough current during heavy use, and the phone would turn off even though the battery shows charge remaining.
You will see this slowdown mentioned in Peak Performance Capability. The message will say something like "This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power." Once iOS detects this, it reduces processor speed to keep the phone running.
You can turn off this slowdown in the same Battery Health & Charging screen, but Apple warns that your phone may shut down without warning if you do. Most people leave it on. If the slowdown bothers you, battery replacement is the real solution.
How to get your battery replaced
Apple replaces batteries at Apple Stores and authorized service providers. The cost is usually $69 for most iPhone models, though the price varies slightly by model. If your phone is under one year of warranty or covered by AppleCare+, the replacement is free.
You do not need to make an appointment for a battery replacement at most locations, but calling ahead is faster. Bring your phone and a form of ID. The replacement usually takes one to two hours, though some stores may ask you to come back the same day or the next day if they are busy.
If your battery health is above 80% and your phone is not shutting down unexpectedly, Apple will not replace it under warranty. You can still pay for a replacement if you want, but it is not necessary for the phone to work.
Third-party battery replacements and their risks
Independent repair shops and mail-in services offer battery replacements for $30 to $50, which is cheaper than Apple. However, non-Apple batteries may not hold charge as long, and some third-party replacements do not include the same safety testing.
Using a non-Apple battery will not damage your phone, but you lose some protections. Apple batteries are tested to work with iOS power management, and they include safety features to prevent overcharging. A third-party battery works, but the fit may be slightly loose, and the health reporting in Settings may not be accurate.
If you choose a third-party replacement, use a shop with good reviews and ask whether they use original Apple parts or aftermarket batteries. Original parts cost more but are more reliable.
Signs your battery needs replacement before you check the percentage
You do not have to wait for the health percentage to drop before you notice a problem. If your phone shuts down at 20% or 30% battery, even though it shows charge remaining, your battery is failing. If your phone gets hot during normal use, or if it drains from 100% to 50% in an hour of light use, those are also signs of battery wear.
Unexpected shutdowns are the most common reason people replace batteries. The phone has power, but the battery cannot deliver it fast enough, so iOS cuts power to protect the hardware. Once this starts happening, replacement is the only fix.
If your phone is slow and you suspect the battery, check Battery Health & Charging first. If the health is below 80% and Peak Performance Capability says your phone has been slowed, slowness is probably the battery, not a software problem.
How to extend your battery health as long as possible
Charge your phone in a cool environment. Heat is the biggest enemy of battery life. If your phone gets warm while charging, move it away from direct sunlight or remove a thick case. Avoid leaving your phone in a hot car or in the sun for long periods.
Avoid letting your battery drain to zero regularly. Charging from 20% to 80% is easier on the battery than draining it completely and charging to 100%. If you use your phone heavily, charge it during the day instead of waiting until the battery is nearly dead.
Enable Optimized Battery Charging in Settings > Battery > Battery Health & Charging. This feature learns your charging patterns and slows charging to 80% until you need the phone, then finishes charging closer to when you wake up. It reduces the time your battery spends at 100%, which extends its life.
Frequently Asked Questions
What battery health percentage means I need a replacement?
Apple does not set a specific threshold, but most people notice performance issues between 70% and 80%. If your phone is shutting down unexpectedly, replacement is worth considering regardless of the percentage. If the health is below 50%, you should replace it soon.
Can I check my battery health on an older iPhone?
Battery Health & Charging is available on iPhone 6 and later. If you have an iPhone 5s or older, the feature does not exist in Settings. You can still get a battery replacement at Apple, but you cannot see the health percentage yourself.
Does checking battery health drain my battery?
No. Opening Settings and reading the battery health percentage uses almost no power. You can check it as often as you want without affecting your battery.
Why does my battery health drop so fast?
Heat is the main cause. If your phone gets warm during charging or use, the battery degrades faster. Check whether you are charging in a hot room, using a thick case, or running heavy apps while charging. Reducing heat can slow the decline.
Will replacing my battery make my iPhone feel new again?
If slowness is caused by battery wear, yes — a new battery will restore normal speed. If your phone is slow for other reasons, a battery replacement will not help. Check Peak Performance Capability first to see whether iOS has actually slowed your phone.