Refresh Rate Test
Measure the frames per second your screen really draws — is that 144Hz monitor actually at 144Hz?
How to use the Refresh Rate Test
- Keep this tab in front and press Measure.
- Leave it alone for three seconds while it counts frames.
- Read the result — it should match your display setting.
About the Refresh Rate Test
Bought a 120Hz phone or a 144Hz monitor and want to know it is actually running at that rate? This counts requestAnimationFrame callbacks for three seconds and reports the result in Hz, along with the frame count and the typical gap between frames in milliseconds.
The headline number comes from the median frame gap rather than the average, on purpose. A single stall while the page settles would drag an average down and make a perfectly good 144Hz screen look like 110Hz. The median ignores that one bad frame and reports the rate you are really getting, while the average is still shown underneath if you want to compare the two.
The honest limitation: this measures how fast the browser is drawing, which normally matches your display but is not guaranteed to. A background tab gets throttled hard, so keep this tab in front and do not switch away while the three seconds run. Some browsers and some power-saving modes cap animation at 60fps no matter what the panel can do, and a phone may drop to a lower rate on its own to save battery. If the number is lower than you expected, check those before blaming the hardware. The screen resolution checker and device info fill in the rest of the picture.
Frequently asked questions
How does this measure my refresh rate?
It asks the browser for an animation callback on every frame for three seconds, records the gap between each one, then converts the median gap into a figure in Hz. A 60Hz screen gives gaps near 16.7 ms, 120Hz near 8.3 ms, and 144Hz near 6.9 ms.
Why does it use the median instead of the average?
Because one hiccup ruins an average. If the page stalls for 100 ms while something loads, the mean drops noticeably and a healthy screen looks broken. The median frame gap shrugs that off and reports what nearly every frame actually did. The average is still displayed so you can see when a run was rough.
My 120Hz screen reports 60Hz. Is it faulty?
Usually not. Check that the tab was in front for the whole test, that the device is not in a battery-saving mode, and that the high refresh rate is switched on in the display settings. Some browsers also cap animation at 60fps regardless of the panel, in which case the screen is fine and the browser is the ceiling.
Do I need to keep the tab in front?
Yes. Browsers throttle animation frames in background tabs to save power, so switching away mid-test produces a meaningless low number. Start the test and leave it alone for the three seconds.
Is this the same as my monitor refresh rate setting?
It is the rate the browser managed to draw at, which normally equals the display rate but is not read from the display itself. If the browser or the operating system is capping frames, the tool reports the cap, because that is genuinely what you are seeing on screen.