Battery Status Test
View browser-reported charge level, charging state, and available time estimates on supported laptops and mobile devices.
When the Battery Status API is available, the page reports current charge percentage, charging state, and browser-provided timing estimates. Run once on battery and once while connected to power; allow time for the operating system to update its estimate.
What does this test measure?
When the Battery Status API is available, the page reports current charge percentage, charging state, and browser-provided timing estimates.
Why is this test important?
View browser-reported charge level, charging state, and available time estimates on supported laptops and mobile devices.
How do you run the test?
Run once on battery and once while connected to power; allow time for the operating system to update its estimate.
How should results be interpreted?
A changing estimate can be normal because workload, brightness, battery age, charging control, and the operating system continually recalculate it.
Normal and problematic results
A changing estimate can be normal because workload, brightness, battery age, charging control, and the operating system continually recalculate it.
Technical limitations
Most browsers do not expose design capacity, cycle count, temperature, wear percentage, or calibrated battery health.
Why can the score decrease?
Unstable measurements, denied permissions, unsupported browser APIs, background load, power saving, or an incomplete test can affect the result. When a score changes, the result screen explains the reason.
What should you do if a problem is found?
Check operating-system battery reports, power mode, charger and cable, manufacturer diagnostics, and unexpected background activity.
Example Result Explanation
Frequently Asked Questions
Why can the browser not show my battery health?
Battery wear, cycle count and design capacity live at operating-system level and are deliberately closed to websites. A browser can read charge level and charging state only, so the honest answer here is a blank rather than a guess.
What is the difference between battery level and battery health?
Level is how full the battery is right now. Health is how much capacity it has lost since it was new. A battery can read one hundred percent full while holding far less energy than it originally did.
No battery information appears at all. Why?
Desktop computers have no battery to report, and several browsers removed the battery interface entirely for privacy reasons. Both cases show as unavailable rather than as an error.