If you want one table for "what should my battery health be", this is it — built from Apple's published cycle ratings rather than from forum folklore. For the mechanism behind the numbers, see Battery Health Explained.
Apple's published cycle ratings
| Models | Rated cycles | Health retained | Roughly equivalent to |
|---|---|---|---|
| iPhone 15 and later (incl. 16, 17, 18 series) | 1000 | 80% | ~3 years at one full charge per day |
| iPhone 14 and earlier | 500 | 80% | ~1.5–2 years at one full charge per day |
Apple also publishes a figure that surprises people: on iPhone 15 and later, the battery is designed to retain 80% after 1000 cycles *under ideal conditions* — and Apple explicitly says using the device in very hot conditions can permanently shorten battery life. That is the single biggest variable you control.
What counts as a cycle. One cycle = discharging 100% of capacity in total. Charging from 50% to 100% twice is one cycle, not two. Check yours at Settings → Battery → Battery Health & Charging; on iPhone 15 and later the cycle count itself is shown on the same screen.
What to expect at each stage
| Age (typical use) | 1000-cycle model | 500-cycle model | What it means in practice |
|---|---|---|---|
| New | 100% | 100% | Full capacity, full peak performance |
| ~1 year | ~95–98% | ~90–95% | No noticeable difference |
| ~2 years | ~90–95% | ~82–88% | Still fine; check if you feel lag |
| ~3 years | ~85–90% | ~78–82% | 500-cycle models are at or past the line |
| Below 80% | — | — | Peak performance may be limited — this is the published threshold |
Read the table as a range, not a promise. Heat exposure moves these numbers more than charging habits do, and two identical phones used differently can differ by 10 points after two years.
The 80% line: what actually changes
Below 80% maximum capacity, the battery's fully-charged voltage can no longer support the processor at full speed, so iOS deliberately limits peak performance. The result is the classic "my old phone became slow" experience — lag, heat and erratic percentage jumps arriving together. See Battery Health Explained for the mechanism.
That is also why the number is a replacement line and not a failure state:
- When capacity gets low, iOS may additionally show a Service message (Apple does not publish the exact threshold)
- A replacement restores the performance, not just the number — see How Long Does an iPhone Battery Last
- Above 80% with no felt difference, waiting is reasonable. The payoff from replacement is about experience, not the percentage
The habits that actually move these numbers
Of everything that ages a battery, heat is first:
- Avoid heat while charging — charging in the sun, under a pillow, in a hot car, or while gaming. See Why Charging Makes Your Phone Hot
- Don't hold it at 100% for hours — turn on Optimized Battery Charging, or set a charge limit if your model supports it: Charge Limit: Is 80% Worth It?
- Don't store it at full charge — Apple's guidance for long-term storage is around 50%
Everything else — third-party "battery saver" apps, full discharges to "calibrate", charging overnight — ranges from useless to counterproductive. See iPhone Battery Saving.