Refresh-rate testEN

How to use it

This estimates the cadence observed by the browser tab. It is useful for a quick check, not a certified measurement of the panel’s hardware mode.

1. Move the runner to the display you want to inspect and close heavy tabs or applications.
2. Open the runner in a new tab. Fullscreen is optional and must be requested separately.
3. Keep the runner visible, start the measurement, and wait up to eight seconds; Stop remains available.

Worked example

Input

Median foreground frame interval about 16.67 ms

Output

Approximately 60.0 Hz

The estimate is 1000 divided by the median usable interval after warm-up.

Method and definitions

• The first 20 valid intervals are warm-up samples; at least 60 later intervals are required.
• Intervals above 250 ms or not greater than zero are discarded, then a median resists occasional long frames.
• Measurement ends after eight seconds or 360 usable intervals and stops if the tab becomes hidden.

Limits and edge cases

• Variable refresh, multiple displays, power saving, thermal load, compositor scheduling and browser throttling affect results.
• Background tabs, remote desktops and virtual machines may not expose the physical display cadence.
• The value is approximate and is not a hardware certification, overclock validation or motion-quality score.

Privacy

Frame timestamps and the estimate exist only in this tab and are never uploaded or stored.

Sources

• MDN — Window.requestAnimationFrame()
• MDN — prefers-reduced-motion
• MDN — Fullscreen API
• MDN — Guide to the Fullscreen API
• W3C — WCAG 2.2 Three Flashes or Below Threshold