Check Your Battery Level and Charging Health
Read live battery status from your browser: charge level, charging state, time to full, estimated runtime and the measured charge rate over the session.
What This Battery Test Shows
A quick, private way to inspect laptop, tablet and phone battery behaviour
Charge Level
Live battery percentage with colour coding so a low charge is obvious at a glance
Charging State
See instantly whether the device is charging or running on battery power
Time Estimates
Time until fully charged and the estimated remaining runtime reported by the OS
Charge Rate
Measured percentage gained or lost per minute during the test session
Level History
A live chart of the charge level so you can spot drops, stalls or fast charging
Fully Local
Battery data stays in your browser. Nothing is uploaded or stored on a server
How to Test Your Battery
Four steps to check battery level and charging behaviour
Open the test
The battery status is read automatically when the page loads - no button press needed
Unplug or plug in
Disconnect the charger to see runtime estimates, or connect it to measure the charge rate
Watch the chart
Leave the page open for a few minutes so the chart collects enough samples to show a trend
Compare results
Note the estimated runtime at different charge levels to judge how much capacity your battery has lost
Browser Compatibility
The Battery Status API is only exposed by some browsers
Chrome
Full SupportFull support on desktop and Android
Edge
Full SupportFull support on Chromium-based Edge
Firefox
Full SupportNot supported - API removed for privacy
Safari
Full SupportNot supported - API not implemented
Frequently Asked Questions
Common questions about testing battery health in a browser
Why does the battery test show no data?
Your browser does not expose the Battery Status API. Firefox and Safari do not provide it. Open this page in Chrome or Edge on a device with a battery to see live values.
Can a website measure my battery's real health percentage?
No. Browsers only report the current charge level and charging state. Design capacity, cycle count and cell voltage are not exposed, so a true wear percentage requires the manufacturer's diagnostic tool or system battery report.
What does the charge rate tell me?
It shows how fast the battery gains charge per minute. A very low rate on a fast charger can indicate a weak cable, a busy CPU, or an aging battery that can no longer accept full current.
Why does the remaining time change so often?
The operating system recalculates runtime from current power draw, so heavy tasks such as video playback or compiling will shorten the estimate. It is a rough projection, not a measurement.
Should I keep the page open?
Yes. The chart and the charge rate need samples over time. Browsers may throttle timers in background tabs, so keep this tab in the foreground for the most accurate trend.
Is my battery data sent anywhere?
No. Everything is processed locally in your browser. Charge level, charging state and history never leave your device.