What Is a Battery Status Tool?
This tool reads your device's real, live battery data - current charge percentage, whether it's plugged in and charging, and estimated time remaining - directly from the browser's Battery Status API, where that API is available. Support for this API has narrowed significantly across browsers over the past several years specifically due to privacy concerns, and this tool reports that limitation honestly rather than faking a battery reading it can't actually obtain.
How to Use the Battery Status Tool
- Load this page on a device with a battery, using a supporting browser.
- Check your current battery percentage and charging status.
- Plug in or unplug your device and watch the values update live, automatically.
- Check the time estimates for a rough sense of charge time remaining or time until empty.
How It Works
Where supported, this tool calls navigator.getBattery(), which returns a live
BatteryManager object exposing your device's real charge level, charging state, and time
estimates. This tool listens for that object's change events, so the display updates automatically the
moment your actual battery state changes - plugging in, unplugging, or simply draining over time - without
needing to refresh the page.
Understanding Your Results
- Battery level and charging status update live and accurately - your browser supports the API and is reporting genuine hardware data.
- Time estimates show " - " - this is common; many systems don't calculate a reliable time estimate in every charging state, and this is reported honestly rather than showing a fabricated number.
- "Not supported" message - this reflects your specific browser's current implementation, not a hardware fault; the API has been removed entirely from Firefox and Safari.
- Desktop shows "Unavailable" - expected for a device without a battery at all.
Browser Limitations
The Battery Status API has been deliberately removed from Firefox and Safari, and its availability in Chrome has narrowed in certain contexts, specifically because researchers demonstrated that precise battery data (particularly time estimates) could contribute to tracking users across sessions. Where the API is available, it currently works only in Chromium-based browsers on most platforms; this tool cannot work around that limitation, since it reflects a deliberate browser privacy decision rather than a technical gap this tool could bridge.
Common Mistakes to Avoid
- Assuming "Not supported" means your battery is broken - it almost always reflects which browser you're using, not your device's actual battery health.
- Testing on Firefox or Safari and expecting a reading - try a Chromium-based browser like Chrome or Edge instead, since those currently offer the broadest support.
- Relying on time estimates as precise predictions - they're system-calculated estimates that can shift based on your current usage, screen brightness, and running applications.
Frequently Asked Questions
Why was the Battery Status API removed from some browsers?
Researchers demonstrated that precise, frequently-updating battery data could be combined with other signals to help track and identify users across browsing sessions, leading Firefox and Safari to remove the API entirely as a privacy protection.
Is my battery data sent anywhere by this tool?
No. All battery data is read and displayed entirely within your browser and is never transmitted or stored anywhere.
Why do the time estimates sometimes show " - "?
Not every device and charging state produces a reliable time calculation; when the browser itself doesn't provide a usable estimate, this tool shows that honestly rather than inventing a number.
Does this work on a desktop computer?
Only if your desktop has a reportable battery, such as one connected to a UPS that exposes battery data - a typical desktop without any battery hardware will show the status as unavailable.
Can I use this to monitor my battery health over time?
This tool shows live current status only; it doesn't track history between sessions, since nothing is saved after you leave the page.
Conclusion
Where supported, this gives you a genuine, live view of your battery's real state straight from your browser - and where it isn't supported, an honest explanation of why, rather than a fabricated reading. For a broader look at your device's other hardware signals, check Device Information.