Apple shows how much maximum capacity a device’s battery still has, compared to a new one. That’s called battery health. If battery health is 96% and the batter

Apple shows how much maximum capacity a device’s battery still has, compared to a new one. That’s called battery health. If battery health is 96% and the battery is charged at 50%, it holds 0.96 * 0.50 = 0.48 times the charge of a new battery, i.e. 48%. If battery health becomes too low a device’s speed can be reduced to preserve running time of the device. That’s what got Apple into problems before (“Apple is intentionally crippling devices”), see “Batterygate”: https://en.m.wikipedia.org/wiki/Batterygate https://en.m.wikipedia.org/wiki/Batterygate