iPhone Battery Health, Explained Simply

Open Settings, then Battery, then Battery Health & Charging, and you'll see a percentage. That number is Maximum Capacity — how much charge your battery can hold today compared to when it was new. It is the single most useful health metric on any iPhone, and the first thing we measure on every trade-in.

What the numbers mean in practice

Above 90%: effectively new — you will not notice a difference. 85–90%: healthy daily driver; most one-to-two-year-old phones live here. 80–85%: still fine, but heavy users will charge twice a day. Below 80%: Apple considers the battery consumed — expect shorter days and possible peak-performance throttling. Replacement is worth it at this point.

Habits that genuinely help

Heat is the real enemy, not charging habits. Avoid leaving the phone on a car dashboard or charging under a pillow. Enable Optimised Battery Charging, and don't stress about overnight charging — the phone manages itself.

Every pre-owned iPhone we sell lists its exact measured battery health, and we never sell below 80%.