How to Check Laptop Battery Health on Windows, MacBook and Chromebook

Windows 10 and 11: the battery report

Right-click the Start button and open Terminal (or Command Prompt).
Type powercfg /batteryreport and press Enter.
Windows saves a file called battery-report.html and shows where. Open it in a browser.

Near the top, under Installed batteries, compare two numbers:

Design capacity: what the battery held when it was new.
Full charge capacity: what it holds now.

Divide the second by the first. 42,000 mWh out of 50,000 mWh is 84% health. The report also shows the cycle count on many laptops and, further down, how long the battery lasted on a charge over recent weeks.

Some manufacturers add their own tools too: Lenovo Vantage, Dell Power Manager and MyASUS all show battery health and let you set a charge limit.

MacBook

Settings → Battery, then the ⓘ button next to Battery Health, shows Normal or Service Recommended, and on recent macOS versions the maximum capacity percentage.
For the cycle count, hold Option, click the Apple menu and choose System Information. Go to Hardware → Power and look for Cycle Count.

Apple rates most modern MacBook batteries for 1,000 cycles before they drop to about 80% capacity.

Chromebook

Open the Diagnostics app (search for it from the launcher). The battery section shows its health, cycle count and current power draw.
On newer ChromeOS versions, Settings → Device → Power shows the same information.
Or press Ctrl + Alt + T to open Crosh and type battery_test.

What the numbers mean

Above 90%: close to new.
80–90%: normal wear for a laptop a couple of years old.
Below 80%: noticeably shorter battery life; a replacement is worth pricing, especially on a used laptop you are about to buy.
Cycle count: useful on its own when buying used. A two-year-old laptop with 800 cycles has worked much harder than one with 150.

What a browser test adds

Websites can’t read battery health, but our laptop diagnostic checks the parts the reports above don’t: every key, the trackpad, webcam, microphone, speakers, USB ports and screen. In Chrome and Edge, the battery test also shows whether the charger is actually charging the laptop, which is worth checking with the seller’s own charger.

Warning signs

The laptop shuts down suddenly with charge left, or only runs on the charger.
The trackpad clicks stiffly or the case bulges near it. That can be a swollen battery pushing up underneath. Stop using the laptop and have the battery replaced.
Windows shows “Plugged in, not charging” with a charger that should work. Check the charge-limit setting in the manufacturer’s app first; it is often set on purpose.

Buying a used laptop? The used laptop checklist covers BIOS locks, ports, the hinge and everything else.