Refresh rate measures how many times a second your screen redraws — 60Hz, 120Hz, 144Hz, 240Hz and so on. It watches your browser’s animation frames to estimate the rate and frame time, and the moving square below lets you eyeball how smooth motion looks. Close other heavy tabs for the cleanest reading. Nothing is uploaded.

— Hz

measuring…

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live FPS

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frame time (ms)

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jitter (ms)

The square should glide smoothly — stutters mean dropped frames.

The rate is estimated from the time between animation frames over a couple of seconds, taking the most common interval so a few hiccups don’t skew it. Browsers cap animation at the display’s refresh rate, so this reads your real Hz on a healthy system; background load, battery-saver modes, or a browser throttling the tab can lower it. Frame time is 1000 ÷ Hz; jitter is how much it varies. Everything runs on your device.