Battery questions, fixes and result guides.
Practical answers for common battery problems, confusing results and setup questions — with a direct path back to the live test.
How do I check my laptop battery health on Windows 11?
Open Command Prompt and run powercfg /batteryreport, then open the generated HTML file and compare Design Capacity with Full Charge Capacity. The battery page on this site shows the live charge level and links the same steps.
What is a good battery health percentage?
Above 80% of design capacity is generally fine. Between 70% and 80% you will notice shorter runtime, and below 70% a replacement is usually worth considering if you use the laptop away from a charger.
Why does my laptop battery drain so fast?
Common causes are a worn battery, high screen brightness, background apps and sync, a demanding browser workload, or battery saver being off. Check the OS battery report for wear first, then check which apps use the most energy.
Is 100% charge the same as 100% battery health?
No. Charge level only says the battery is full right now. Health compares remaining capacity with design capacity — check the OS battery report on the page for the real number.
Why does the battery page show nothing in Safari or Firefox?
Those browsers do not expose the Battery API for privacy reasons. Use the Windows battery report, macOS System Report or Linux upower steps on the page instead.
How accurate is this battery tool?
Charge level is not battery health. Browsers cannot read remaining capacity or cycle count; that needs the OS battery report.
What should I do if the battery result looks wrong?
If the page says the Battery API is unavailable, your browser hides it (Safari and Firefox do) — use the Windows battery report, macOS System Report or Linux upower steps on the page instead.