Refresh Rate & Frame Pacing Test
Measure your display’s real refresh rate and how evenly your browser delivers frames. The test samples animation-frame timestamps for five seconds and reports the estimated refresh rate, the spread of frame times and how many frames arrived late.
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About this tool
The browser draws one frame each time the display refreshes, so the gap between frames reveals the refresh rate. The test records those gaps for five seconds, finds the median and compares it with common rates such as 60, 120 and 144 Hz.
It measures the display and the browser, not GPU speed. It cannot detect variable refresh rate (G-Sync, FreeSync, ProMotion), so a reading below your panel’s maximum does not always mean a problem. Keep the tab in the foreground while it runs.
How to read the results
Estimated refresh rate. Calculated from the median time between frames. A 144 Hz monitor should show about 6.94 ms. If it reports 60 Hz, the operating system, a power-saving mode or the browser may be limiting it.
Jitter. The standard deviation of frame times. Under 0.3 ms is excellent; above 1 ms usually means background load or a power-saving state.
Late frames. Frames that took more than one and a half times the median. A handful in the first second is normal while the page warms up.
Frequently asked questions
Why does my 144 Hz monitor show 60 Hz?
Check the refresh rate in your operating system's display settings, use a DisplayPort or HDMI cable that supports it and turn off battery saver. Some browsers also cap background or unfocused windows.
Is the result affected by my GPU?
Only indirectly. The browser caps animation to the display rate, so a faster GPU does not raise the number. A very weak or busy GPU can cause late frames.
What counts as a late frame?
A frame that took more than one and a half times the median interval.
Why does it read slightly off, for example 59.9 Hz?
Displays rarely run at exactly 60.000 Hz. The tool also shows the closest standard rate for reference.
Can it detect G-Sync or FreeSync?
No. Variable refresh rate is not visible to a web page.
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