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How to check laptop battery health and when to replace the battery

Updated October 30, 2026

All laptop batteries lose capacity as they age. If yours barely lasts through a meeting, Windows can tell you exactly how worn it is in under a minute. Here's how to check, what the numbers mean and what to do next.

Step 1: create a battery report

Right-click Start and open Terminal (Windows 11) or Windows PowerShell / Command Prompt (Windows 10).
Type powercfg /batteryreport and press Enter.
Windows says where it saved battery-report.html — usually your user folder (C:\Users\YourName). Open it in your browser.

Step 2: read the numbers

In Installed batteries, compare:

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

Divide full charge by design capacity. For example, 34,000 mWh ÷ 50,000 mWh = 68% of original capacity, meaning about 32% wear.

80% or more remaining: healthy for its age.
60–80%: noticeably shorter runtime; replace if it bothers you.
Below about 60%: a replacement will make a clear difference.

Also look at Cycle count (if listed) and the Battery capacity history table to see the trend. The Battery life estimates section shows how long it lasts at the current capacity versus when new.

Our free scan reads the same two capacity numbers and calculates the wear for you.

Warning signs: stop using it

Shut the laptop down, unplug it and don't charge it if you notice:

The case, touchpad or keyboard bulging or lifting, or the bottom cover no longer sitting flat — signs of a swollen battery.
A sweet or chemical smell, hissing, or unusual heat.

Don't press on or puncture a swollen battery. Get it replaced by the manufacturer or a repair shop.

Make the battery you have last longer

Turn on battery saver and use Settings › System › Power & battery (Windows 11) to see which apps use the most power.
Lower screen brightness and close apps running in the background.
Many laptop makers offer a charge limit setting (e.g. stopping at 80%) in their own app or BIOS. If you mostly use the laptop plugged in, this slows wear.
Avoid leaving it in hot places like a car.

Replacing the battery

Find the right part

Find your laptop's exact model (on the bottom label or in msinfo32 as System Model).
Look up the battery part number in the manufacturer's support site or by checking the label on the old battery.
Buy a genuine battery from the manufacturer or a reputable seller that lists your exact part number, voltage and capacity. Avoid unusually cheap unbranded batteries — poor-quality cells are a safety risk.

Who should do it

Removable or screwed-in batteries: many business laptops and some consumer ones have a battery held by screws under the bottom cover. With the manufacturer's service guide, a careful beginner can do this.
Glued batteries: in many thin laptops the battery is glued in. Use the manufacturer's repair service or a repair shop.
Under warranty: check first — some warranties cover batteries that wear unusually fast.

DIY steps (screwed-in batteries)

Shut down fully (hold Shift while clicking Shut down to avoid Fast Startup), unplug the charger.
Remove the bottom cover screws and gently pry the cover with a plastic tool.
Disconnect the battery connector first, then remove the battery screws and lift it out.
Fit the new battery, connect it, replace the cover.
Charge it to full before regular use and check the new numbers with a fresh battery report.

Recycle the old one

Never put lithium-ion batteries in household trash. Take them to a battery recycling drop-off; many electronics stores and local hazardous waste sites accept them. Tape over the terminals first.

Battery or new laptop?

If the battery is the only problem, a replacement is usually far cheaper than a new laptop. If the laptop is also slow, out of storage or can't run Windows 11, see upgrade or replace.