How to check battery health on iPhone and Android

Every lithium-ion battery wears out. After a couple of years, a phone that used to last until bedtime may need a top-up by mid-afternoon. Before you blame an app or buy a new phone, it is worth checking the battery itself. This guide shows where to find battery health on the most common phones, how to read the figures, and when a replacement is the better deal.

What "battery health" actually measures

Battery health is usually shown as maximum capacity: how much charge the battery can hold now, compared with when it was new. A battery at 85% stores about 85% of its original energy, so a full charge lasts roughly 15% less.

Two other numbers help:

• Charge cycles. One cycle is 100% of capacity used, whether in one go or as several partial top-ups (for example, two days of using 50%). Wear builds up with cycles, as well as with heat and age.
• Peak performance. Old batteries struggle to deliver short bursts of high power. Some phones then limit the processor to avoid sudden shutdowns, which can make a phone feel slow.

These figures are estimates made by the phone's battery management software. They are useful for spotting a trend, not as a lab measurement.

How to check battery health on an iPhone

1. Open Settings → Battery → Battery Health (on newer iOS versions it may read Battery Health & Charging).
2. Look at Maximum Capacity. Below it, Peak Performance Capability tells you whether the battery can still support normal peak performance.
3. On iPhone 15 and later, go to Settings → General → About to see the cycle count, plus the battery's manufacture date and first use.

Apple says batteries in iPhone 14 and earlier are designed to keep 80% of their original capacity at 500 complete cycles, and those in iPhone 15 and later at 1,000 cycles, under ideal conditions. If iOS can't verify the battery or it has degraded significantly, you'll see a Service message on this screen.

How to check battery health on a Samsung Galaxy

Samsung's most reliable built-in check is in the Samsung Members app, which comes preinstalled on most Galaxy phones:

1. Open Samsung Members and tap Support (or Get help).
2. Choose Phone diagnostics, then Battery status.
3. The test reports the battery's condition (for example Normal or Weak) and, on many models, its life and capacity.

Some recent Galaxy models running newer versions of One UI also show battery information directly in Settings. Menu names vary by model and software version; our list of phones getting One UI 9 and Android 17 shows which Galaxy devices are getting the newest software.

How to check battery health on a Google Pixel

On recent Pixels (Pixel 8a and newer models), go to Settings → Battery → Battery health. It shows an estimated maximum capacity and an overall status, and some models also show the cycle count under Settings → About phone → Battery information. Older Pixels don't show capacity in Settings.

Other Android phones

Xiaomi, OnePlus, Oppo, Honor, Motorola and others each handle this differently:

• Look in Settings → Battery first. Many brands now include a "Battery health" or "Battery information" page.
• Try the brand's support or diagnostics app. Several manufacturers include a built-in hardware test.
• The testing menu. On some Android phones, dialling *#*#4636#*#* opens a hidden testing menu with basic battery information. Many phones block it, and it won't damage anything if it doesn't work.
• Third-party apps estimate capacity by watching how much charge goes in over several charges. Give them a few days of normal use and treat the result as a rough guide. Install them only from trusted developers; our guide to spotting fake apps on Google Play explains what to check.

How to read the numbers

These bands are a general rule of thumb, not manufacturer specifications. Symptoms matter more than the exact percentage. Replace the battery, or have it checked, if you notice any of these:

• The phone shuts down suddenly at 20–30% or in the cold.
• The percentage jumps up and down, or drains very fast under light use.
• The phone feels slow and battery health shows reduced peak performance.
• The back or screen is lifting, or the case no longer fits. That can be a swollen battery: stop charging the phone and get it to a repair shop.

Heat speeds up wear and is also a symptom of an ageing battery. If your phone runs hot, our guide on why phones overheat and how to cool them down covers the usual causes.

Replace the battery or the phone?

A new battery can make an older phone feel new again, and it usually costs far less than a new handset. It is the better choice when:

• the phone still gets security updates for a few more years;
• it is otherwise fast enough for what you do;
• the screen and body are in good shape.

Use the manufacturer's service or an authorised repair shop where possible. Cheap batteries of unknown origin may not deliver their stated capacity or may lack proper safety protection. If the phone is near the end of its update support, putting the money towards a new one often makes more sense.

How to slow down battery wear

• Avoid heat. Don't leave the phone in a hot car or charge it under a pillow, and take off thick cases if it gets warm while charging.
• Use charge limits. Many phones can stop at 80% or learn your routine and finish charging just before you wake up (Apple's Optimized Charging, Samsung's battery protection, Pixel's Adaptive Charging and similar features).
• Don't worry about the occasional full charge or running low now and then; regular deep discharges and long periods at 100% in heat are what add up.
• Use a good charger. Fast charging is designed to be safe, but a certified charger and cable matter. See our USB-C charger guide, and our power bank buying guide if you need extra charge on the go.