Know your phoneFor everyone5 min read

How to check your phone's battery health

Check battery health on an iPhone, a Samsung Galaxy or a Pixel, spot a worn or swollen battery on any phone, and see how battery condition affects price.

In short

On an iPhone, Battery Health in Settings shows maximum capacity, and below 80 percent the battery is worn.
On Android, use Samsung Members on a Galaxy or Settings on a Pixel 8a or later, but many other phones do not show it.
A swollen battery is a safety risk: stop using and charging the phone and take it to a service centre.

01Why batteries wear out

Every phone battery wears out slowly as it is charged and used. A worn battery holds less charge, so the phone needs charging more often and may shut down without warning.

Apple says iPhone 14 and earlier models are designed to keep 80 percent of their original capacity after 500 full charge cycles, and iPhone 15 and later after 1,000, under ideal conditions. Google says Pixel 8a and later should keep up to 80 percent for about 1,000 cycles.

A charge cycle means using 100 percent of the battery's capacity in total, not in one go. Using half the battery on two different days adds up to one cycle.

02On an iPhone

01
Open Battery Health
Go to Settings > Battery and tap Battery Health. On some models and iOS versions it is called Battery Health & Charging.
02
Read Maximum Capacity
This compares the battery with when it was new, so 100 percent means as good as new. Below 80 percent, the battery is worn enough that a replacement is worth considering.
03
Find the cycle count on iPhone 15 and later
Scroll down the same screen to see the cycle count, the battery's manufacture date and its first use. Older iPhones do not show a cycle count in Settings.
04
Note any messages
If the screen recommends service, or says it cannot verify that the battery is a genuine Apple battery, write it down. A buyer will ask about both.

03On an Android phone

Android phones vary. Some show battery health in Settings, some in a brand app, and many not at all.

Samsung Galaxy

01
Open Samsung Members
The app usually comes preinstalled on Galaxy phones. Go to the Support tab.
02
Run phone diagnostics
Under Phone diagnostics, tap Get started and let the checks finish.
03
Tap Battery status
The result is Normal, Weak or Bad. Samsung suggests visiting a service centre for advice if it shows Weak or Bad. Menu names can differ by model and app version.

Google Pixel 8a and later

01
Battery health
Go to Settings > Battery and tap Battery health. Normal means the battery is within normal limits. Reduced means its capacity has dropped below 80 percent, and Google recommends replacing it.
02
Cycle count
Go to Settings > About phone and tap Battery information for the cycle count, the manufacture date and the date of first use.

04Signs of a worn battery on any phone

The charge drops much faster than it used to, even with light use.
The phone switches off at 20 or 30 percent, or the percentage jumps suddenly.
It gets hotter than it used to while charging or during simple tasks.
It slows down, especially when the battery is low.
It only stays on while plugged in.

05How battery health affects the price

Anyone buying a used phone thinks about when the battery will need replacing, and adjusts the offer to match.

A healthy original battery helps a phone keep its grade and its price.
A worn battery lowers the offer, even on a phone that looks new.
A non-original battery can lower it further. On recent iPhones, a replaced battery shows in Settings > General > About under the parts and service history.
A recent battery replacement at an authorised service centre helps, especially if you keep the invoice.

Replacing the battery just before you sell is only worth it if it raises the price by more than it costs. If you are not sure, ask the shop what it would offer either way.

At a Recashy partner shop the phone is checked in front of you, so you can see the battery reading the shop is going by.