Laptop battery check online. Charge, charging, time left.
A quick read of what the browser knows about the battery. It is not a health test, and the page says so; for wear and cycle count, the system's own report is the honest source.
One check
- Battery
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
In short
Battery check: the answer first
A browser battery test reads what Chrome and Edge share about the battery: the charge level, whether it is charging, and the time left where the system estimates it. It is not a health test, and the page says so.
Reading your result
- Nothing reported
- Safari and Firefox do not expose battery data. That is the browser, not the battery.
- Charging state changes speed
- Laptops run slower on battery by design. Note the state before reading any performance result.
- Wear needs the system report
- Design capacity against current capacity and the cycle count come from the system's own battery report.
What it measures
Measured here, not assumed.
- Charge level
- As a percentage, from the browser's battery interface in Chrome and Edge.
- Charging state
- Plugged in or on battery, which changes how fast a laptop runs.
- Time left
- The system's estimate at the current drain, where it gives one.
If it fails
The usual failures, and what fixes each.
- Nothing is reported
- Safari and Firefox do not expose battery data. Open the page in Chrome or Edge, or use the system's battery report.
- Charge drops fast
- Check what is using power in the system's battery settings, lower the screen brightness, and run the battery report to see the design capacity against the current one.
Where a browser stops
What it cannot tell you.
- Battery health, wear and cycle count. No browser exposes them; use the system's battery report.
- Anything at all in Safari or Firefox, which do not share battery data.
- Whether the battery is the reason a laptop is slow. The stress test measures that.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Battery check, answered
- Can a website check my battery health?
- No. Browsers share only the charge level, charging state and a time estimate, and only in Chrome and Edge. Health needs the system report: the system's battery report (powercfg on Windows, System Information on a Mac, Battery Health on a phone).
- Why is my laptop slower on battery?
- Laptops lower their power limits on battery to last longer. The free stress test run once plugged in and once on battery shows how much speed that costs.
- Is the time left estimate accurate?
- It is the system estimate at the current drain, so it moves with what you are doing. Treat it as a guide, and plug in before anything that matters.
- How do I check battery health properly?
- On Windows, the battery report from the command line; on a Mac, the battery section of System Information. Both show capacity and cycles, which a browser cannot read.
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