Charge cycles and battery wear: how long a phone battery will last

A charge cycle is using the battery's full capacity (100%), whether in one go or in parts. Battery wear is the gradual loss of capacity with every cycle and with age. Its condition is shown as "battery health" - a percentage of the original capacity.

A battery wears out like the sole of a trainer

In plain words

Think of trainers. Every kilometre wears the sole a little. It does not matter whether you ran 10 km in one go or one kilometre a day for ten days - the wear is the same. A charge cycle is that "kilometre" for a battery. Heat, running on sharp rocks and sudden sprints are like heat and charging to 100% overnight: they wear it faster.

How it works

Discharging from 100% to 50% and recharging, then doing it again, adds up to one cycle.
With each cycle, some of the lithium and electrode material "tires".
Capacity gradually drops - for example, to 80% after several hundred or a thousand cycles.
Wear is sped up by high temperatures, long periods at 100% and deep discharges to 0%.
The system shows battery health and cycle count in the settings.

Heat is a battery's worst enemy

Where you'll see it

On iPhone: Settings > Battery > Battery Health & Charging; on many Android phones, in the battery settings or service menus. Manufacturers state how many cycles the battery keeps 80% capacity for: 500, 1000, 1600 and more.

Does it matter when buying

Yes, if you keep your phone for several years. My simple rules: avoid heat (do not leave the phone in the sun or game while charging), turn on optimised charging or an 80% limit, and do not leave the phone at 0% for long. When health drops below 80%, it is time to think about a battery replacement.

Myths

Myth: A new battery should be drained to zero a few times. Reality: That is a myth from old battery days. Deep discharges only harm lithium-ion batteries.
Myth: Charging in short bursts harms the battery. Reality: The opposite - partial charges are normal and even beneficial.

FAQ

How many cycles does a phone battery last?

Usually 500 to 1000+ cycles to 80% capacity, depending on the model.

Can the battery be replaced?

Yes, at a service centre; from 2027 the EU will require phone batteries to be easier to replace.

How do I check battery health on Android?

In the battery settings on some brands, or through service apps.