How to check your laptop battery’s health in Windows

Why Settings will not tell you

Windows 11’s Settings → System → Power & battery shows how full the battery is and which apps use it, but on most laptops not how worn it is. That figure is in the battery report, which Windows can produce on any laptop in a few seconds.

Create the battery report

1. Right-click the Start button and choose Terminal (on Windows 10, Windows PowerShell). If the command below reports an error, choose Terminal (Admin) instead.
2. Type powercfg /batteryreport and press Enter.
3. Windows replies with where it saved the report, usually C:\Users\your name\battery-report.html. In an administrator window it is C:\Windows\System32\battery-report.html. Open that folder in File Explorer and double-click battery-report.html: it opens in your browser.

Read the two numbers that matter

Under Installed batteries, near the top of the report:

• Design capacity is what the battery held when it was new, in milliwatt-hours (mWh).
• Full charge capacity is what it holds now when fully charged.

Divide the second by the first and you have the battery’s health. A battery designed for 57,000 mWh that now holds 45,600 mWh is at 80%. The same section shows the cycle count, the number of full charges it has been through; not every battery reports one, and a dash means yours does not.

Further down, Battery capacity history shows how the full charge capacity has changed week by week, and Battery life estimates compares how long the laptop ran on a full charge with how long it would have run when the battery was new. A slow slide is normal wear. A sudden drop is worth watching: it can be a failing cell, or a reading the battery corrects after its next full charge and discharge.

What the numbers mean

Health	What it means
80–100%	Normal. Batteries lose a few percent a year with ordinary use, and a new one often reports slightly more than its design capacity.
50–80%	Worn. The laptop runs noticeably less on a charge. Many laptop makers treat 80% as the end of a battery’s rated life.
Below 50%	Worth replacing if you use the laptop away from a socket. Windows itself may show Consider replacing your battery.

Whatever the figure, if the battery has swollen — the touchpad lifts, the case bulges or no longer closes flat — stop using and charging the laptop and have the battery replaced. A swollen lithium battery can catch fire.

Make the battery last longer

• Do not keep it at 100% all day. If the laptop is plugged in most of the time, switch on the maker’s charge limit, which stops charging at around 80%: Lenovo Vantage calls it Conservation Mode, Dell Primarily AC Use, ASUS Battery Health Charging and HP Battery Health Manager.
• Keep it cool. Heat wears a battery fastest: gaming with the vents against a duvet or a lap, or leaving the laptop in a hot car.
• Store it half full. For a laptop put away for weeks, leave the battery at about half charge rather than flat or full.
• Check what is using the charge. A short battery life is not always the battery. Settings → System → Power & battery → Battery usage shows which apps use the most; screen brightness, game launchers and browser tabs running in the background are the usual ones.

Replacing the battery

The Name field under Installed batteries is usually the battery’s part number. Search for it together with your laptop’s model to find the right replacement, and buy the laptop maker’s own part or from a reputable seller: an unbranded battery that is far cheaper is where safety corners get cut. Many laptops hold the battery with screws behind the bottom panel; in some it is glued, and the maker’s service or a repair shop is the safer route.

How Bottleneck checks this

Bottleneck reads the battery’s design capacity, full charge capacity, charge cycles and type straight from the battery, through the same part of Windows the battery report uses, and shows its health on the Components page as a percentage of its original charge. That is part of every scan, in the free version too. A battery holding less than 80% is reported among the findings, with what to do about it.