Make the report
Open Command Prompt or PowerShell, type this, and press Enter:
Windows saves a file called battery-report.html in the folder the window is open in, usually your user folder. The window shows the full path. Double-click the file to open it in your browser.
Two options are useful. /output lets you choose where the file goes, and /duration sets how many days of history the report covers:
Installed batteries: the part that matters most
This table describes each battery in the laptop. Laptops with two batteries list both. These are the fields:
- NAME
- The battery's model or part code. Useful when you're shopping for a replacement.
- MANUFACTURER
- Who made the cells. This is often a supplier, not your laptop's brand.
- SERIAL NUMBER
- The battery's own serial, separate from the laptop's.
- CHEMISTRY
- The battery type, usually lithium-ion (LION) or lithium polymer (LiP).
- DESIGN CAPACITY
- How much energy the battery was built to hold, in milliwatt-hours (mWh). This number doesn't change.
- FULL CHARGE CAPACITY
- How much it actually holds today when charged to 100%. This is the number that drops as the battery wears.
- CYCLE COUNT
- How many full charge cycles the battery has been through. Some batteries don't report it and show a dash.
To get battery health, divide full charge capacity by design capacity. A battery designed for 57,000 mWh that now holds 44,960 mWh is at about 79%, so it gives you roughly four-fifths of its original runtime.
Recent usage and battery usage
These sections log recent days: when the laptop was active or asleep, whether it was on battery or plugged in, and how fast the charge dropped. Dell's guide suggests using them to spot unexpected drain, such as an app that kept the laptop from sleeping. If your battery dies overnight in a bag, this is where to look first.
Usage history
A longer view of how much time the laptop spent on battery versus plugged in, broken into periods. It tells you how you actually use the laptop, which matters when you're deciding whether a worn battery is a problem for you.
Battery capacity history
Each row is a time period with two numbers: full charge capacity and design capacity. Read down the full charge column to see the wear trend. A slow, steady decline is normal aging. A sudden drop over a few weeks is worth paying attention to.
Don't read too much into one row. Full charge capacity moves up and down by a few percent with temperature and recent charging habits.
Battery life estimates
Windows estimates runtime two ways: at the battery's current full charge, and at its design capacity. The gap between the two columns is the runtime you've lost to wear.
Drop your battery-report.html into the CheckMyBatt battery check and it pulls out the health, wear, cycle count and capacity history for you. The file is read in your browser and never uploaded.