Battery Status Checker
See your battery percentage, whether it is charging and how long until it is full or empty. The page updates live and keeps a log of every change while it is open.
Battery level this session
The chart fills in as the level changes.
Change log
| Time | Event | Level | Charging | Estimate |
|---|---|---|---|---|
| No readings yet. | ||||
Supported in Chrome, Edge, Opera and Samsung Internet. Safari and Firefox do not let web pages read the battery.
How to use the Battery Status Checker
- Open the page on the laptop, phone or tablet you want to check. The reading starts automatically.
- Press Check battery to refresh the reading at any time.
- Read the gauge: the percentage, whether the device is charging, and the estimated time to full or empty.
- Leave the page open to build up a log. After a few changes the tool shows your measured rate per hour.
- Export the log as CSV if you want to compare sessions or chargers.
What the battery readings mean
| Reading | What it tells you | Notes |
|---|---|---|
| Level | Charge from 0% to 100% | Some systems round it to whole or 5% steps |
| Charging | Whether a charger is connected | Can say "yes" even when a full battery is just being topped up |
| Time to full | Seconds until 100% while charging | Often shown only after a few minutes of charging |
| Time to empty | Seconds until 0% on battery | Depends on what you are doing right now, so it moves around |
| Measured rate | Percent gained or lost per hour, worked out by this page | Uses the level changes logged since you opened the page |
How the measured rate is worked out
Every time the level changes, the tool records the time and the new level. While the charging state stays the same, the rate is rate = (last level − first level) ÷ hours elapsed. The time left is then the remaining percentage divided by that rate.
Example: the battery drops from 82% to 76% in 30 minutes. That is −6% in 0.5 h, or −12% per hour, so the remaining 76% lasts about 76 ÷ 12 = 6 h 20 min.
Tips to make your battery last longer
- Lower the screen brightness. The display is usually the biggest drain on phones and laptops.
- Close busy tabs and apps, especially video, games and video calls.
- Turn on battery saver or low power mode when you are away from a charger.
- Avoid heat. High temperatures shorten battery life more than anything else.
- Keep it between about 20% and 80% for day-to-day use if your device offers an optimized or limited charging option.
Browser support
The Battery Status API works in Chromium-based browsers on Windows, macOS, Linux, Android and ChromeOS. Safari, every browser on iPhone and iPad, and Firefox do not expose it, so this page will show a clear message there instead of a reading. Desktop computers without a battery usually report 100% and charging.
Frequently asked questions
Why does it say the Battery API is not supported?
Only Chromium-based browsers such as Chrome, Edge, Opera and Samsung Internet expose the Battery Status API. Safari and Firefox removed or never shipped it for privacy reasons, so web pages cannot read the battery there. Use your system's battery settings instead.
Why does my desktop computer show 100% and charging?
Computers without a battery report a full, charging battery to web pages. That is the standard behavior of the Battery Status API, not an error.
How accurate are the time to full and time to empty estimates?
They come from the browser and the operating system, which often only report them after the level has changed a few times. The tool also measures its own rate from the log, which becomes more reliable the longer the page stays open.
Does this check battery health or capacity?
No. Browsers only expose the charge level, charging state and time estimates. Battery health and cycle counts are available in your operating system, for example in System Settings on macOS or with powercfg /batteryreport on Windows.
Is any data sent anywhere?
No. The readings are shown only in this page and are not stored or uploaded. The log disappears when you close the tab unless you export it.
Why does the level change in steps of 1% or more?
Some systems round the level to whole percentages or even to 5% steps before passing it to the browser, so small changes can take a while to appear.