How to Check Your iPhone’s Battery Health (and What the Numbers Mean)
Your iPhone tells you exactly how worn its battery is. Here's where to find the numbers, how to read them, and when a replacement actually makes sense.
To check your iPhone’s battery health, open Settings > Battery > Battery Health (on iPhone 14 and earlier the item is usually called Battery Health & Charging). The key number is Maximum Capacity: anything above 80% is normal wear, and a reading below 80% is the point where most people start to notice shorter battery life and should consider a replacement.
Below, we explain each number on that screen, where to find your charge cycle count, and how to decide whether a new battery is worth it.
How to find Battery Health on your iPhone
- Open the Settings app.
- Scroll down and tap Battery.
- Tap Battery Health (or Battery Health & Charging on older models and older iOS versions).
- Read the Maximum Capacity percentage and any message under Peak Performance Capability.
Menu names have shifted slightly between iOS releases, so if you don’t see the exact wording, look for anything with ‘Battery Health’ in the Battery menu. Apple’s own explanation of these readings is on its iPhone battery and performance page.
What the numbers mean
Maximum Capacity
This compares your battery’s current capacity to when it was new. A brand-new iPhone shows 100%. At 90%, a full charge holds roughly 90% of the energy it originally did, so you’ll get somewhat less screen time per charge. The number drops slowly over months and years; that’s normal chemistry, not a fault.
Peak Performance Capability
This section tells you whether the battery can still deliver the bursts of power the phone needs. The message you want to see is that your battery is currently supporting normal peak performance. If the iPhone has had an unexpected shutdown because the battery couldn’t keep up, iOS may turn on performance management, which slightly limits peak speed to prevent more shutdowns. You’ll see a note about it here, and you can turn it off, but it may turn back on after another shutdown.
Service messages
If iOS detects a significantly degraded battery, it shows a message recommending service. If it can’t verify the battery (for example, after a repair with a non-genuine part), it may say so. Either way, a visit to Apple or an authorized service provider is the next step.
How to see your charge cycle count
A charge cycle is using the equivalent of 100% of your battery, not necessarily all at once. Using 60% today and 40% tomorrow adds up to one cycle.
- iPhone 15 and later: the cycle count, manufacture date and first-use date are shown directly on the Battery Health screen. On some iOS 17 builds, they appeared under Settings > General > About instead.
- iPhone 14 and earlier: iOS doesn’t display the cycle count in Settings. An Apple Store or authorized service provider can run a diagnostic that shows it.
How many cycles should a battery last?
Apple publishes design targets for how much capacity a battery should keep under ideal conditions:
| Model | Design target |
|---|---|
| iPhone 14 and earlier | About 80% of original capacity at 500 complete charge cycles |
| iPhone 15 and later | About 80% of original capacity at 1,000 complete charge cycles |
Real-world results vary with heat, charging habits and usage. A phone that is often charged in a hot car or used for gaming while charging will usually wear faster than one kept cool.
When should you replace the battery?
Use these rules of thumb:
- Above 85%: no action needed. If battery life seems poor, the cause is more likely an app or setting (check Settings > Battery for apps using a lot of power).
- 80–85%: watch it. If the phone still gets you through the day, there’s no rush.
- Below 80%, or a service message: a replacement will typically make the phone feel close to new again, especially if you plan to keep it another year or two.
- Unexpected shutdowns, especially in the cold or at 20–30% charge, are a strong sign the battery is worn regardless of the percentage.
If your iPhone is covered by AppleCare+ and the battery has dropped below 80%, Apple replaces it at no extra cost. Out of warranty, a genuine Apple battery replacement for recent models typically costs around $100 or more in the US, depending on the model; check the exact estimate for your model on Apple’s support site before booking. A genuine battery also keeps the Battery Health readings working properly.
How to slow down battery wear
- Keep the charging optimizations on. In Settings > Battery > Charging (iPhone 15 and later) you can choose options such as limiting the charge to 80%. On older models, keep Optimized Battery Charging turned on under Battery Health & Charging.
- Avoid heat. High temperatures are the biggest enemy of lithium-ion batteries. Don’t leave the phone in direct sun or a hot car, and remove thick cases if the phone gets warm while charging.
- Don’t worry about small top-ups. Partial charges are fine. There’s no need to drain the battery to 0% first.
- Keep iOS updated. Updates sometimes improve battery management and fix bugs that drain power.
Bottom line
Check Settings > Battery > Battery Health once in a while. Over 80% Maximum Capacity is healthy; below 80% or a service warning means a replacement is worth considering. On iPhone 15 and later you can also see the cycle count, which helps you judge how hard the battery has been used, especially when buying a used iPhone.
FAQ
Is 85% battery health bad?
No. 85% is normal wear for a phone that’s a year or two old. You’ll get somewhat shorter battery life than when new, but the battery is still within Apple’s expected range.
Can I restore battery health to 100%?
No. Battery wear is chemical and permanent. Calibration tricks or apps can’t bring capacity back. The only way to get back to 100% is a new battery.
Why did my battery health drop quickly after an update?
After some updates, iOS recalibrates its estimate, and the number can shift a few points. If it drops sharply or a service message appears, contact Apple Support for a diagnostic.
Does fast charging damage the battery?
Apple’s fast charging is designed to slow down as the battery fills, so normal use is fine. Heat is what matters most, so avoid fast charging in hot conditions where possible.
