To check your iPhone’s battery health, open Settings, tap Battery, then tap Battery Health on an iPhone 15 or later, or Battery Health & Charging on an iPhone 14 or earlier. The number that matters on that screen is Maximum Capacity: how much charge the battery can hold now compared with when it was new, as Apple’s battery and performance page defines it. A new phone reads 100 percent, or just under it; the figure falls slowly as the battery chemically ages. Apple designs the battery in an iPhone 14 or earlier to retain 80 percent of its original capacity at 500 complete charge cycles, and the iPhone 15 series and later to retain 80 percent at 1,000 complete cycles, under ideal conditions — so the same percentage means different things on different models, and the 80 percent area is where Apple starts talking about service. No app or website can read this number for you; the Settings screen is the source, and it takes under a minute.
| Your iPhone | Tap after Settings > Battery | What you will see |
|---|---|---|
| iPhone 15 and later (iOS 17.4 or later) | Battery Health | Maximum Capacity, cycle count, manufacture and first-use dates, service recommendation |
| iPhone 14 and earlier | Battery Health & Charging | Maximum Capacity, Peak Performance Capability, optimised charging switch |
| Any model, battery draining fast today | Battery (the screen before) | Last 24 hours and last 10 days of usage by app |
The check, step by step
- Open the Settings app.
- Tap Battery.
- Tap Battery Health (iPhone 15 and later) or Battery Health & Charging (iPhone 14 and earlier). Apple’s current iPhone guide gives the same path and says the screen shows information about your battery’s capacity, peak performance, and whether your battery needs to be serviced.
- Read Maximum Capacity first. Then read the line underneath it — on newer models whether a replacement is recommended, on older models the Peak Performance Capability message.
If the menu name on your phone does not match either label, the phone is usually on an older iOS than the guides assume, or the battery is not a genuine Apple part: Apple warns that if you see a message that the battery cannot be verified, the health information on that screen may not be accurate. Update iOS first (Settings > General > Software Update), then look again.
What Maximum Capacity actually means
Maximum Capacity is a comparison, not a fuel gauge. In Apple’s words, it measures the device battery capacity relative to when it was new: a battery will have lower capacity as it chemically ages, which might result in fewer hours of usage between charges. A phone at 92 percent has not lost 8 percent of its day in any precise sense — it holds roughly 92 percent of the charge it held when new, and everything else (screen brightness, signal, workload) still decides how long that charge lasts.
Three readings of the number are worth having:
- High 90s to 100: normal, including on a phone some months old. Apple notes that depending on the time between when the iPhone was made and when it was activated, capacity might show as slightly less than 100 percent straight out of the box. That is storage time, not damage.
- Mid-80s to low 90s: a visibly ageing battery. The phone works normally, but heavy days end sooner, and this is the range where checking the screen once in a while — rather than once ever — starts to make sense.
- Around and below 80: the service zone, covered next.
The second line on the screen matters as much as the percentage. Peak Performance Capability tells you whether the battery can still deliver the instant power the phone asks for. The healthy message reads Your battery is currently supporting normal peak performance. If the phone has ever shut down unexpectedly because the battery could not deliver peak power, iOS applies performance management to prevent a repeat, and the screen says so — the phone may feel slower not because the percentage is low, but because iOS is deliberately capping peaks to keep it alive. A significantly degraded battery produces its own message, pointing you to an Apple Authorized Service Provider to restore full performance and capacity; Apple is clear that this message is not a safety warning and the phone remains usable.
The 80 percent line, and Apple’s cycle figures behind it
Eighty percent is not a folk threshold invented by forums; it is the figure Apple’s own design targets are built around. From Apple’s page on iPhone 11 and later: batteries of iPhone 14 models and earlier are designed to retain 80 percent of their original capacity at 500 complete charge cycles under ideal conditions, and batteries of iPhone 15 models and later are designed to retain 80 percent at 1,000 complete charge cycles under ideal conditions. Two consequences follow.
First, judge a percentage against the right target. An iPhone 13 at 84 percent after heavy use is a battery approaching the end of its designed span. An iPhone 16 at the same 84 percent would be wearing unusually fast for a battery designed to reach 1,000 cycles before touching 80 — the same number, a different story, and a stronger case for asking Apple about it while any warranty or coverage lasts.
Second, “designed to retain” is a design figure under ideal conditions, not a promise about your phone. Apple says the exact capacity percentage depends on how the devices are regularly used and charged. Heat, in particular, ages a battery faster than use does. Falling a little short of the design line is wear; falling far short, early, is the pattern worth a service conversation — and if a Service message appears on the Battery Health screen itself, Apple recommends considering replacement regardless of the exact percentage.
Cycle count: where it lives depends on the model
A charge cycle is not one plug-in. You complete one cycle when you have used an amount equal to 100 percent of the battery’s capacity — 50 percent today and 50 percent tomorrow is one cycle, as Apple’s footnote puts it, with a complete cycle normalised between 80 and 100 percent of original capacity to allow for the expected decline. The cycle count is therefore the battery’s mileage, and it is the figure to read alongside Maximum Capacity when you are buying or selling a used phone.
Where you read it splits by model, and this is the detail guides most often get wrong by stating one location as if it were universal:
- iPhone 15 and later, with iOS 17.4 or later: the count is on the Battery Health screen itself. Apple states that on these models you can see the battery health and maximum capacity, whether a replacement is recommended, the cycle count, when the battery was manufactured, and when it was first used — all from Settings > Battery > Battery Health. On these models the same details have also appeared under Settings > General > About, which is why some guides give that path instead; either way, it is a built-in Settings readout, two or three taps away.
- iPhone 14 and earlier: there is no cycle count line in Settings. The phone records the figure, but iOS does not surface it on the Battery Health & Charging screen, which shows capacity and peak performance only. The on-phone route to it is the diagnostic log: Settings > Privacy & Security > Analytics & Improvements > Analytics Data, open the most recent file whose name begins with Analytics followed by a date, and search the text for the cycle count entry. That only works if Share iPhone Analytics has been on long enough for logs to exist — turn it on and the files appear after a day or so of use. A computer with a battery utility reading the phone is the other route. Treat any guide that sends an iPhone 12 owner to a Settings screen for this number as out of date.
A screenshot of the Battery Health screen is the cleanest record for a sale or a repair visit — how to screenshot on Windows is the desktop side of that habit; on the phone itself, the side button plus volume up does it.
Optimised charging: the setting that slows the decline
Checking health once tells you where the battery is; the charging settings decide how fast it falls from there. The main one is Optimised Battery Charging. Apple’s page on charge limits and optimised charging explains that it is designed to reduce wear by reducing the time the iPhone spends fully charged: when enabled, the phone delays charging past 80 percent in certain situations, using on-device machine learning to learn your daily routine so it finishes charging in time for when you usually unplug. It is on by default, shows a Lock Screen notification with the expected finish time when it is active, and can be overridden from that notification with Charge Now when you need a full battery sooner.
Where the switch lives again depends on the model:
- iPhone 15 and later: Settings > Battery > Charging. Here you choose a Charge Limit between 80 and 100 percent in 5 percent steps; the phone charges to within a few points of the limit and stops. Optimised Battery Charging is available when the limit is set to 100 percent. If iOS judges a limit would help, it may show a recommendation based on your habits.
- iPhone 14 and earlier: Settings > Battery > Battery Health & Charging, then turn Optimised Battery Charging on or off. Apple warns that turning charging optimisations off can increase wear and reduce lifespan.
Two honest caveats. Optimised charging needs time to learn — Apple says at least 14 days, and at least nine charges of five hours or more in a given location, before it engages — so a phone that charges to 100 percent in its first fortnight is not faulty. And a battery that drains quickly today is a different question from a worn battery: the Settings > Battery screen itself shows the last 24 hours and up to the last 10 days of usage by app, which is where a single runaway app shows up. A phone that feels full and slow at the same time may have a storage problem rather than a battery one — see iPhone storage full: system data.
Frequently asked questions
What is a good battery health percentage for an iPhone? Anything in the 90s is a healthy battery. The 80s mean visible ageing but normal operation. Around 80 percent is Apple’s own design and service reference point — below it, expect the Battery Health screen to raise service, and expect noticeably shorter days.
How do I check the cycle count on my iPhone? On an iPhone 15 or later with iOS 17.4 or later, open Settings > Battery > Battery Health and read the Cycle Count alongside Maximum Capacity. On an iPhone 14 or earlier there is no Settings readout; the figure sits in the Analytics logs under Settings > Privacy & Security > Analytics & Improvements > Analytics Data.
Why is my new iPhone at 99 or 98 percent already? Apple says capacity can show as slightly less than 100 percent depending on how long passed between the phone being made and being activated. Early movement of a point or two is normal storage and settling behaviour, not a defect.
Does checking battery health need an app? No. The figure comes from iOS itself, and no website or third-party app can read your battery’s maximum capacity more accurately than the Settings screen that Apple documents — on an iPhone, browsers cannot access battery health data at all.
Can I check iPhone battery health on a Windows PC or a Mac? Not with Apple’s own computer apps. Apple’s Windows app and Finder on a Mac handle syncing, backups, updates and restoring — neither shows Maximum Capacity or the cycle count. Some third-party computer tools read the figures the phone reports over a USB cable, which is one way to see a cycle count on an iPhone 14 or earlier. But the reading still comes from the phone itself, so for your own iPhone the Settings screen gives you the same number with no cable and no extra software.
Can battery health go back up? No — not in any real sense. Capacity loss is chemical ageing, and good habits only slow it down; they do not reverse it. The percentage can move a point when iOS recalibrates its estimate, but that is the estimate changing, not the battery recovering. The only way back to 100 percent is a new battery. Be wary of any app or shop that promises to restore battery health.
When should I actually replace the battery? When the screen tells you to — a Service message or a replacement recommendation — or when the combination in front of you (capacity around or below 80 percent, performance management applied, days that no longer last) makes the phone unreliable for how you use it. Apple directs battery service to Apple or an Apple Authorized Service Provider, and notes that health figures from a battery that cannot be verified as genuine may not be accurate — its genuine batteries page covers how to check what is fitted via Settings > General > About.
This article is general information, based on the Apple Support pages linked above and checked in November 2026. Menu labels differ between iPhone 15 and later and iPhone 14 and earlier, and between iOS versions; if a label on your phone differs slightly, you are in the right place if Maximum Capacity is on the screen in front of you.