Screen refresh rate test
Press Start and the page counts how often your browser draws a new frame for about two seconds. The median frame time gives your refresh rate in Hz, rounded to a common display rate such as 60, 120 or 144.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Close heavy tabs and plug in a laptop if you can.
- Press Start test and leave the page visible for two seconds.
- Read the rounded Hz and the exact measured rate under it.
How it works
The test collects the gap in milliseconds between animation frames. The first three are discarded because the page is still warming up. The median of the rest is used rather than the average, so one slow frame does not skew the answer. Refresh rate is 1000 divided by the median gap, in Hz.
Worked example
If the median gap is 6.94 ms, the rate is 1000 / 6.94 = 144.1 Hz, within 3 percent of 144, so the page shows 144 Hz. A median of 10 ms gives exactly 100 Hz, which is not near a listed rate, so it is shown as 100 Hz.
Tips
- Result lower than the specification? Check the display setting in your operating system first.
- Battery saver. Many phones and laptops cap animation at 30 or 60 Hz when it is on.
- Compare modes. Run the test again after changing the refresh rate in system settings.
Frequently asked questions
How does the test work?
It records the time between consecutive requestAnimationFrame callbacks for about two seconds, drops the first three frames, and takes the median. The rate is 1000 divided by that median frame time.
Why do I get 60 Hz on a 144 Hz monitor?
The display may be set to 60 Hz in the system settings, or the browser may be limited. Battery saver modes on laptops and phones, power-saving profiles and some remote desktop sessions cap the frame rate.
Why is the measured rate not a round number?
Real frame times jitter a little. The page shows the exact measured rate and also a rounded value, which snaps to 60, 75, 90, 120, 144, 165 or 240 Hz when within 3 percent of one of them.
Does a background tab matter?
Yes. Browsers slow animation frames in hidden tabs to save power, which would make the result wrong. Keep the tab in front during the test.
Is variable refresh rate (G-Sync or FreeSync) measured?
No. The page sees only what the browser delivers. Adaptive sync is usually not used by web pages, so you see the display's maximum or its set mode.