Battery Test & Health Checker
Watch your battery live in the browser, and check its real health from a Windows, macOS or Linux battery report. Everything runs on your device. Nothing is uploaded.
Want deeper details (design capacity, wear %, cycle count)? Pick your OS, run the command so the report is copied to the clipboard, then press Analyze.
- Open Command Prompt (CMD).
- Paste and run the command above.
- Return to this page and click Analyze (allow clipboard access if asked).
Battery details
Fields marked “Not available” are not exposed by the browser or your OS report (for example live voltage and milliwatt charge rate need a desktop utility).
Capacity over time (% of design capacity)
Your file is read by this page only. It is never sent to a server.
| Time | Level | State | Event |
|---|
The log records every level change and charger event, plus a line every minute. On a desktop PC without a battery, browsers report 100% and "charging".
What this battery test can and can't measure
Browsers share only a small amount of battery information with websites: the charge level, whether a charger is connected, and the device's own time estimates. This page adds a running log and a measured drain or charge rate (percent per minute) on top of that.
Battery health, meaning how much capacity is left compared with when the battery was new, isn't available to websites. Your operating system does record it, so the Battery Health Report section reads the report your system can produce and turns it into a clear health score.
How to get a battery report (Windows)
- Open Command Prompt (CMD).
- Run this command (saves the report and copies it to the clipboard):
powercfg /batteryreport /output "%USERPROFILE%\Downloads\battery-report.html" && clip < "%USERPROFILE%\Downloads\battery-report.html" - Return to this page and click Analyze. The site reads the clipboard and analyzes the report automatically — no manual paste or file upload needed.
macOS and Linux commands
macOS and Linux do not support Windows’ powercfg /batteryreport. Use these instead — they copy battery information to the clipboard (not the same detailed HTML history report Windows creates).
| Operating system | Command | Clipboard output |
|---|---|---|
| Windows | powercfg … && clip < … | HTML battery report |
| macOS | system_profiler SPPowerDataType | pbcopy | Battery / power text |
| Linux (X11) | upower … | xclip -selection clipboard | Battery text (needs upower + xclip) |
| Linux (Wayland) | upower … | wl-copy | Battery text (needs upower + wl-clipboard) |
On macOS, paste with Command + V only if you need the text elsewhere — for this tool, just click Analyze after running the command.
Battery health percentage guide
| Battery health | Battery wear | Condition |
|---|---|---|
| 95–100% | 0–5% | Excellent |
| 85–94% | 6–15% | Very good |
| 75–84% | 16–25% | Good, some wear |
| 65–74% | 26–35% | Moderate wear |
| 50–64% | 36–50% | Significant wear |
| 40–49% | 51–60% | Heavily worn |
| Below 40% | Over 60% | Severely worn |
Frequently asked questions
Why does my desktop PC show 100% and charging?
Without a battery, the browser has nothing to report, so it shows a full battery that is plugged in.
Why doesn't live status work in Firefox or Safari?
Those browsers don't offer battery information to websites, for privacy reasons. Battery Health Report (file upload) works in every browser.
Is my battery report uploaded anywhere?
No. The file is read and analyzed inside your browser. Nothing leaves your device.
Why does the health report say it can't find capacity values?
Windows writes the report in your system language. This tool reads English labels first and then falls back to the capacity numbers. If it still fails, paste the text of the report.
What is a normal amount of battery wear?
Lithium-ion batteries lose capacity gradually with use and age. Many laptop batteries are still around 80% after a few hundred full charge cycles, but it varies by model and how the battery is treated.