How the refresh rate test works
Browsers draw animations once per screen refresh. This page asks to draw a new frame over and over, times the gap between each one, and takes the typical gap from the last couple of seconds. A gap of 16.7 ms means 60 frames a second (60 Hz); 6.9 ms means 144 Hz. "Slow frames" counts recent gaps that took much longer than usual, which shows up as stutter.
The moving square gives you something to watch: on a higher refresh rate it glides more smoothly across the bar.
Not getting the rate you paid for?
- Pick the rate in your settings. On Windows, open Settings › System › Display › Advanced display and choose a refresh rate. On macOS, open System Settings › Displays.
- Check the cable and port. High refresh rates usually need DisplayPort or a recent HDMI cable plugged into your graphics card, not the motherboard.
- Turn off battery saver. Laptops and phones often drop to 60 Hz to save power.
- Test one screen at a time. With several monitors, the browser may follow the screen the window is mostly on.
- Close heavy tabs and apps. A busy computer can miss frames, which pulls the result down.
Frequently asked questions
Why does the number wobble slightly?
Each frame's timing varies by a fraction of a millisecond. The closest standard rate is usually the true setting of your display.
My variable refresh (FreeSync or G-SYNC) monitor shows its maximum. Is that right?
Yes. With nothing else to slow it down, the browser runs at the top of your monitor's range.
Why is the result capped at 60 Hz in my browser?
Some privacy settings and power-saving modes limit animations to 60 frames per second. Try a different browser or plug your laptop in.