To check your battery in a browser, open a battery test and read the level and status it shows. The free battery test reads your charge level, whether the device is plugged in and charging, and the estimated time to full or empty, all without installing anything, where your browser supports it.
That is the quick answer. It comes with an important limit worth understanding up front, so let us be clear about what a browser can actually see.
What a browser can and cannot tell you
A web page can read three things about your battery: the current charge level as a percentage, whether the device is charging, and rough time estimates for full or empty. That is genuinely useful for everyday checks, but it is not the whole story.
What a browser cannot read is battery health in the deeper sense: the original capacity, how much of it has been lost to wear, or the charge cycle count. Those figures live in the operating system and the manufacturer’s tools, not in the browser. So this test tells you the live status, not how worn the battery is over its lifetime.
It also will not work everywhere. Several browsers removed battery access for privacy reasons, so on those the test simply reports that the information is not available. That is expected, not a fault.
How to use the battery test
Step 1: Open the page
The battery test reads your status straight away on a supported browser. There is no permission prompt and nothing to install.
Step 2: Read the level and status
You see the charge as a percentage and whether the device is plugged in and charging or running on battery. Plug in or unplug and watch the status switch.
Step 3: Watch the time estimate
When the browser provides it, the test shows the estimated time to full while charging or to empty while discharging, and updates as the level moves.
When this is handy
- Confirming a charger works. Plug in and watch the status flip to charging. If it does not, the cable, adapter or port is the suspect.
- Keeping an eye on the level. Track the percentage from a browser tab without opening system menus.
- Estimating time to full. See roughly how long before the battery is topped up before you head out.
For real battery health, go deeper
If you want to know how much your battery has degraded, check your operating system’s built-in tools. On a laptop there is usually a battery report in the system settings, and phones list battery health in their settings too. Those are the right place for capacity and wear figures.
While you are checking your device, the screen resolution tool and webcam test are quick ways to confirm the rest of it is in good shape.