How the refresh rate test works
Your browser draws a new frame each time the screen refreshes. The test times those frames for a few seconds and matches the result to the nearest standard rate: 60, 90, 120, 144, 165 or 240 Hz. It also counts dropped frames, which show up as stutter in the moving square. A smooth, evenly moving square with few dropped frames means the display and graphics are keeping up.
Why does it show 60Hz on a 120Hz screen?
- Low Power Mode or Battery Saver caps the screen at 60Hz on most phones and many laptops.
- iPhone and iPad (Safari): Safari usually limits web pages to 60 fps, even on ProMotion displays, so a result of 60Hz in Safari is normal. Also check Settings › Accessibility › Motion › Limit Frame Rate is off.
- Samsung Galaxy: turn on Settings › Display › Motion smoothness › Adaptive (or High).
- Google Pixel: turn on Settings › Display › Smooth Display.
- Windows: Settings › System › Display › Advanced display › Choose a refresh rate. On external monitors, a DisplayPort or HDMI 2.0+ cable is needed for 144Hz and up.
- Mac: System Settings › Displays › Refresh rate (ProMotion on MacBook Pro).
- Adaptive displays drop to a lower rate when nothing is moving, which is why the test keeps an animation running.
Dropped frames and stutter
A few dropped frames when the page first loads are normal. Frames dropping all the time point to a busy processor, a laptop running on battery saver, many browser tabs or an overheating device. Close other apps and run the test again. If a gaming monitor still stutters, check the cable and that the correct refresh rate is selected in the graphics driver settings.
Checking the rest of the device? Run the phone diagnostic or the laptop test, or check for dead pixels.
Frequently asked questions
How do I check my screen refresh rate?
Open this page and wait a few seconds without scrolling. It times how often the browser draws a new frame and shows the nearest standard rate, such as 60, 120 or 144 Hz, plus dropped frames.
Why does my 120Hz phone show 60Hz?
Battery saver or Low Power Mode caps most phones at 60Hz, and Safari on iPhone and iPad usually limits web pages to 60 fps. On Samsung turn on Motion smoothness, and on Pixel turn on Smooth Display, then test again in Chrome.
Why does my 144Hz monitor show 60Hz?
Windows may still be set to 60Hz. Open Settings › System › Display › Advanced display and choose the highest refresh rate. Also use a DisplayPort or HDMI 2.0+ cable and connect it to the graphics card, not the motherboard.
Is the refresh rate test accurate?
It measures the rate the browser actually draws at, which matches the display on most devices. Browsers can limit frame rates in power-saving modes or background tabs, so keep the tab in front and plugged in for the most reliable result.