How's your battery?
Your charge level, whether you're plugged in, and how long until full or empty — live from your device.
One moment while we read the battery status from your device.
How the battery test works
This page asks your browser for its Battery Status API (navigator.getBattery)
and, where it's available, subscribes to live updates — so the gauge, percentage and
charging state change in real time as you plug in or unplug. There's no permission
prompt because nothing is captured: the browser simply shares what your operating system
already knows about the battery.
The API is a Chromium thing: Chrome, Edge and Opera expose it, while Firefox and Safari keep battery data hidden from websites for privacy. On those browsers (and on desktops without a battery) the test tells you plainly instead of guessing. Whatever is read stays on your device — nothing is uploaded.
What the readings mean
- Level — your current charge as a percentage, drawn on the gauge.
- Charging — whether power is flowing in right now.
- Time to full / empty — your OS's own estimates; they show "—" while the system recalculates.
- Health hint — a friendly nudge: "Low — plug in" under 20% on battery, otherwise "Looks fine".
Battery test FAQ
Why does it say battery info isn't available?
The Battery Status API is only exposed by Chromium browsers — Chrome, Edge and Opera. Firefox removed it and Safari never shipped it, both citing fingerprinting concerns, so on those browsers this page can't read anything and says so honestly. Try Chrome or Edge to see your readings.
Are the time-to-full and time-to-empty estimates accurate?
They're your operating system's own estimates, passed through untouched — the same maths behind the tooltip on your system battery icon. Right after plugging in or unplugging they often read as — while the OS recalculates. Treat them as a rough guide, not a promise.
Does this test measure battery health or capacity?
No — browsers only expose the current level, charging state and time estimates, so the health hint here is just a friendly read on those. For true wear data, use your OS: on Windows run powercfg /batteryreport, on a Mac check System Information → Power.
I'm on a desktop PC — why does it show 100% and charging?
Machines without a battery typically report themselves as fully charged and plugged in, because that's the closest state the API can describe. It's expected — this test is most useful on laptops, tablets and phones.
Is my battery data uploaded anywhere?
No. The reading happens locally — your browser hands the page the level and charging state, we display it, and that's the end of the trip. Nothing is stored or sent to any server.