Screen Refresh Rate Test

About this tool

Press Start and keep the tab in front for five seconds. The page asks the browser to draw a moving dot as often as it can, which the browser does once for each refresh of the screen, and records the time between the frames. The median of those times gives the refresh rate: 16.7 milliseconds is 60 Hz, 8.3 milliseconds is 120 Hz, 6.9 is 144 Hz and 4.2 is 240 Hz. The result is rounded to a standard rate when it is within 3 percent of one (59.94 shows as 60 Hz); any other value is shown as measured. The page also counts slow frames, which are frames that took one and a half times longer than expected, and shows the jitter, the typical difference between neighbouring frame times. We tested the calculation with simulated frame times for ten standard rates from 30 to 240 Hz, with random timing noise and with dropped frames. The number is what your browser uses, which can be lower than your screen's maximum: the display may be set to a lower rate in the system settings, a power saving mode may be on, the screen may use variable refresh, or the browser may limit animation to 60 Hz. For a fair test, close other tabs and programs and keep this window in front. Everything runs in your browser and nothing is sent anywhere.

How to use it

1. Close other busy tabs and programs.
2. Press Start and keep this tab in front for 5 seconds.
3. Read the rate, the slow frames and the jitter.
4. If the rate is lower than expected, check your display settings.

Common problems

It shows 60 Hz but my screen is 144 Hz

Check the refresh rate in your system's display settings, that the cable and port support it, and that power saving is off. Some browsers also cap animation.

The result is a strange number

Variable refresh rate or a busy computer can give a rate that is not standard. Try again with nothing else running.

The test was interrupted

Browsers pause animation in background tabs. Keep this tab in front during the five seconds.