The big number is the refresh rate your browser is drawing at right now, measured from the screen itself rather than read from a settings page. On a 144 Hz monitor it should say 144. If it says 60, the screen is running at 60 whatever the box promised: a cable, a Windows setting or a power-saving mode is holding it back, and the tests below help you tell which.
What each test shows
- Refresh rate. The rate the screen is actually updating at, with the exact figure, the range over the last two seconds and a count of dropped frames. A steady number with few drops is what you want; a figure that keeps jumping means the browser or the graphics driver cannot keep up.
- Motion. Three ships cross the screen: one moves every frame, one every second frame, one every fourth. On a 120 Hz screen the lanes show 120, 60 and 30 fps side by side, which is the clearest way to see what a higher refresh rate buys you.
- Ghosting. A white square and a striped block move over a grey background. Follow them with your eyes. A faint copy trailing behind, or a dark edge in front, is ghosting or overshoot from the panel’s pixel response, and it is more visible on the Fast setting.
- Frame skipping. Squares light up one per frame, left to right. Take a photo with a quarter-second exposure: an unbroken trail means every frame reached the screen, gaps mean frames were skipped, which happens on overclocked monitors and some TVs.
If the number is lower than expected
Check the refresh rate in the operating system first: Windows hides it under Display settings → Advanced display, macOS under Displays, and many laptops drop to 60 Hz on battery. Then look at the cable: older HDMI and DisplayPort cables cap high resolutions at 60 Hz. On phones, some browsers stay at 60 Hz until the page goes fullscreen, and battery saver limits the screen on most Android models. Running on a second monitor? The browser follows the screen the window is on.
What people use it for
New gaming monitor
Confirm that the 144 or 240 Hz you paid for is what the screen delivers before you start tuning game settings.
Laptop on battery
Many laptops quietly switch to 60 Hz on battery power. A quick check tells you whether the smooth setting is actually on.
Phone with a high refresh screen
See whether the browser gets the full 90 or 120 Hz, or stays at 60 until you go fullscreen or switch off the power saver.
Frequently asked questions
How accurate is the measured refresh rate?
The test times the frames the browser draws, so it matches the screen within a fraction of a hertz when the system keeps up. A browser tab that is throttled, a busy CPU or a screen recorder can make the figure dip below the real rate; the dropped frames counter shows when that happens.
My monitor is 144 Hz but the test says 60. Why?
The browser can only draw as fast as the operating system lets it. Open the display settings and pick the highest refresh rate, make sure the cable supports it, plug a laptop in, and try fullscreen. Some browsers also cap background or non-fullscreen tabs at 60.
What is the difference between refresh rate and frame rate?
Refresh rate is how many times per second the screen can show a new picture, measured in Hz. Frame rate is how many pictures per second the software produces, in fps. A 144 Hz screen showing a 60 fps game still refreshes 144 times a second, but only 60 of them carry new frames.
Does it work on a phone?
Yes. Tap the screen for fullscreen first: on many phones the browser stays at 60 Hz in a normal tab and goes to 90 or 120 Hz only in fullscreen, and the ghosting and motion tests look better on the whole screen anyway.