Quick SupportBattery Run-Time Test
"It used to last all day and now it doesn't." This measures how long your laptop really lasts on a charge — and you don't have to sit here until it dies. It watches how fast the charge actually falls and works the rest out from there.
Nothing is installed and nothing is uploaded. Needs Chrome or Edge — Firefox and Safari removed the battery reading years ago.
This browser won't report the battery
Firefox removed the battery reading in 2017 and Safari never had it — both for privacy reasons, and neither is coming back.
Open this page in Edge — it's already on every Windows machine — or in Chrome, and it'll work.
The Windows battery report further down works whatever browser you're reading this in, and it's the one that tells you about battery health.
Set the test up
Leave this tab in front and don't let the screen sleep — the page will hold the screen awake for you. If you switch away, the computer does less work and the result comes out better than the truth, so we keep track of that and say so.
Measuring…
- Charge
- —%
- Running for
- 0:00
- Using
- —%/hr
- Full charge lasts
- —
Result
Your saved runs
Kept in this browser only. Run one before a new battery and one after, and the pair tells you far more than either on its own.
| Run | Load | Rate | Full charge lasts | Measured over |
|---|
Now check its health — that's the other half
This page measures what your battery delivers. It can't see what it's supposed to deliver, because a browser isn't given the design capacity or the cycle count. Put the two together and you have a real answer rather than a feeling.
- Try the maker's own app first. Lenovo Vantage, Dell Power Manager, MyASUS, HP Support Assistant and the MSI and Acer equivalents all show battery health on a screen with no typing at all. If it's already on your laptop, that's the easiest route.
- Otherwise Windows will write you a report. Press the
WindowsLocated bottom left on your keyboard key, type cmd, press Enter, then paste this in and press Enter:powercfg /batteryreport /output "%USERPROFILE%\Desktop\battery-report.html"CopiedIt puts battery-report.html on your desktop. Double-click it and look for Design Capacity against Full Charge Capacity — that's the wear — plus the cycle count and a table of your real battery life over recent days.
We will never ring you and ask you to type a command
Scam calls start exactly like this — someone claiming to be from Microsoft or your computer shop, walking you through opening a command window. We don't make those calls. If somebody rings you claiming to be us, hang up and ring the shop back on the number you already have.
The command above is Microsoft's own, it only reads information and writes a file to your desktop, and it cannot give anyone access to your computer. Nothing on this page installs anything.