Find Battery Health on your model
Open Settings → Battery. On iPhone 15 and later, tap Battery Health. On iPhone 14 and earlier, tap Battery Health & Charging. Recent models can also show cycle count, manufacture date, and first-use date.
Do not confuse the status bar's 80% charge remaining with 80% Maximum Capacity. The latter compares estimated capacity with the battery when new. Labels can differ by model, installed iOS release, and region, so follow the options shown on your phone.
- Record the iPhone model and iOS version.
- Open Battery Health or Battery Health & Charging.
- Note Maximum Capacity, any Service or performance message, and cycle count if shown.
- Compare recent Battery Usage to separate aging from app activity or weak coverage.
iPhone Duo: check both batteries separately
Apple says iPhone Duo shows a separate Battery Health entry for each of its two batteries. Record each battery's Maximum Capacity, replacement recommendation, and cycle count; one entry does not describe the whole device.
The two batteries can have different manufacture dates and cycle counts. A difference alone does not diagnose a fault. If one entry recommends service, save the exact message and ask Apple or an authorized provider about the appropriate evaluation. We have not tested an iPhone Duo or measured its runtime from these readings.
What does 80% mean?
Apple says iPhone 14 and earlier batteries are designed to retain 80% of original capacity after 500 complete cycles under ideal conditions; iPhone 15 and later batteries are designed for 80% after 1,000 cycles. These are design references, not a promise that an individual phone reaches exactly 80% at a particular cycle count.
Apple's battery service page says eligible AppleCare coverage includes replacement at no extra charge when capacity falls below 80%. Coverage, inspection, local terms, and the final service fee must be checked for your device. An 80% reading is not a universal free-replacement rule.
Swipe the table sideways to see every column →
| What you see | How to interpret it | Next step |
|---|---|---|
| Above 80%, normal use | The number alone does not call for service | Track real runtime |
| Near or below 80% | Capacity has declined; symptoms and coverage matter | Review service options |
| Service or performance message | The phone flags a battery concern | Back up and arrange evaluation |
| Shutdowns, swelling, or deformation | Potential power or safety problem | Stop stressing or charging a damaged phone; seek professional help |
When should you consider replacement?
Consider an Apple evaluation when Battery Health recommends service, the phone repeatedly shuts down unexpectedly, or comparable light use has become impractical. A percentage alone cannot diagnose charger, port, signal, screen, or background-app problems. Check those separately before assuming a new battery is the only fix.
Swelling, a lifted screen, deformation, odor, or unusual heat require prompt professional attention. Do not keep using a damaged battery to wait for a particular percentage, and do not attempt a home battery repair.
- Make and verify a recent backup.
- Save the Battery Health message and relevant usage details.
- Check coverage and local Apple or authorized-provider options; confirm the actual quote.
- After service, verify data and device behavior rather than just one percentage.
If health looks normal but runtime is poor
Use Settings → Battery to inspect Daily Usage, on-screen time, background work, and cellular coverage. Setup or an iOS update can temporarily increase activity. Use the related battery-drain guide to test one likely cause at a time instead of replacing a battery based on one bad day.
Sources were checked October 30, 2026. This is a documentation guide, not a hands-on battery benchmark. We do not predict remaining battery life, quote a universal repair price, or promise a fixed runtime gain after service.