What Is a Refresh Rate Test?
A refresh rate test measures how many times per second your monitor actually redraws the screen, expressed in Hertz (Hz). Manufacturers list a rated refresh rate - 60Hz, 144Hz, 240Hz - but the real number your system delivers can depend on cables, display settings, and GPU output, so measuring it directly is worth doing.
How to Use the Refresh Rate Test
- Move your browser window completely onto the monitor you want to check. Keep the tab visible and, if possible, connect your laptop to power and disable battery saver.
- Choose a test duration (5, 10, 15 or 30 seconds). Start with 10 seconds for a useful sample; longer tests show whether timing stays steady.
- Click Start Test, keep the browser focused and avoid switching tabs, resizing the window, or moving it to a different monitor. The test discards the first half-second as warm-up.
- Watch the live frame-interval graph. When the test finishes, compare Observed Cadence (Hz) with Effective FPS; check the median, P95, jitter and long-interval percentage to understand timing variation.
- Repeat the test to compare runs, and click Export CSV to save the results. Use Stop Early only if necessary; it is marked as a partial run. Reset clears this page's results.
Interpret carefully: the Hz estimate comes from browser animation-frame timing, not a physical sensor in the monitor. A background tab, heavy page load, VRR, power-saving settings or a browser frame cap may make the result differ from the monitor's rated refresh rate. Check your operating system's display settings for the configured rate; a low or inconsistent browser result alone does not establish a hardware fault.
How It Works
This tool uses the browser's requestAnimationFrame API, which the browser calls exactly once
per screen refresh. By counting how many times this callback fires over one second and averaging across
several seconds, the tool estimates your true refresh rate.
This measurement reflects what your browser and OS are actually delivering to the screen - not just what the monitor is rated for in its specifications.
Understanding Your Results
| Measured Hz | Typical Use Case |
|---|---|
| ~60Hz | Standard office/general-use monitors |
| ~75–100Hz | Entry-level gaming monitors |
| ~120–144Hz | Mainstream gaming monitors |
| ~165–240Hz+ | Competitive/esports gaming monitors |
If your measured Hz is noticeably lower than your monitor's rated spec, check your display settings - many operating systems default to 60Hz even on higher refresh-rate monitors until you manually change it.
Benefits
- Confirms your monitor is actually running at its advertised refresh rate.
- Helps troubleshoot a cable or GPU setting limiting your display output.
- Useful when buying a used "gaming" monitor to verify its real performance.
Common Mistakes to Avoid
- Running the test with the window minimized - background tabs are throttled by browsers and will give inaccurate readings.
- Testing on battery-saver mode - laptops often cap refresh rate to save power.
- Expecting an exact match every time - small variance of a few Hz is normal and expected.
Frequently Asked Questions
Why is my measured Hz lower than what my monitor is rated for?
This usually means your display is set to a lower refresh rate in your OS settings, or your cable (especially older HDMI cables) doesn't support the full bandwidth needed for higher refresh rates.
Is this test as accurate as dedicated hardware tools?
It's a very close software-based estimate, but dedicated hardware refresh-rate testers can be marginally more precise since they measure the panel directly rather than through the browser and OS.
Can browser tab throttling affect my results?
Yes. Keep this tab active and in focus during the test - background tabs are intentionally throttled by browsers to save resources, which would give you an artificially low reading.
Does this work for both monitors and laptop screens?
Yes, it works on any display your browser is rendering to, including external monitors, built-in laptop screens, and even some tablets.
Why Advertised Refresh Rate Doesn't Always Match Reality
A monitor labeled 144Hz or 240Hz doesn't automatically run at that rate - it depends on the cable, the GPU port, and whether the right refresh rate is selected in display settings. Older HDMI versions cap out below what DisplayPort can handle at higher resolutions, so a 144Hz monitor on an outdated HDMI cable might silently run at 60Hz. Windows and macOS also sometimes reset to 60Hz after a driver update or waking from sleep. Beyond confirming the number, testing whether frames actually render smoothly matters more, since a weak GPU can't fill a high refresh rate anyway.
Conclusion
Running this test takes just a few seconds and can reveal whether your setup is delivering the refresh rate you're paying for. If results look off, check your display settings and cable, then pair this with the Dead Pixel Test for a fuller screen health check.