Refresh Rate Test

How the estimate works

When you press Start, the page asks the browser to draw a new frame over and over for up to 10 seconds and notes the time of each frame. The middle value of the gaps between frames, the median, gives the estimated rate: a gap of about 16.7 ms means about 60 Hz, 8.3 ms about 120 Hz. Frames that take more than one and a half times the median are counted as long frames. A small square moves steadily across the field so you can also watch for stutter.

1. 1

   Close other heavy tabs and apps, and plug in a laptop, since power saving can lower the rate.

2. 2

   Press Start and leave the page alone for the ten seconds; scrolling or switching tabs disturbs the timing.

3. 3

   Run it two or three times. A steady result is more trustworthy than a single run.

Long frames and stutter

A few long frames in ten seconds are normal: the browser and the system occasionally pause to do other work. Many long frames, or a square that visibly jerks instead of gliding, point to stutter. Closing other apps and tabs, plugging in a laptop, or turning off battery saving often helps. A long frame is a delay in drawing, not a fault in the display.

What the number means

This is the rate your browser is drawing frames at, estimated from frame timing. It usually matches your display's refresh rate, but power saving, background tabs, variable refresh (G-Sync, FreeSync), and browser limits can make it lower. If you expect 144 Hz and see about 60 Hz, check the refresh rate setting in your operating system and the cable or port you are using.

To see how motion looks at that rate, try the Motion Blur / UFO Test; for torn frames, the Screen Tearing Test.