Check the selected system refresh mode, the screen holding this browser window and any mirrored display. Repeat the visible-tab sample before changing one dock, cable or power setting.
Part of the Screen test for dead and stuck pixels. Run the full screen test first for a complete device check.
The observed value stays near 60 Hz The estimate jumps between ranges The tab became hidden during the run
Monitor refresh rate test
Run a monitor refresh rate test and read the frame frequency this browser observes in the current window.
Also known as: monitor refresh rate test, refresh rate test, monitor refresh rate tester, screen refresh rate test online, 120hz test, 144hz test, hz test. Free, online, and no download required.
No permission neededNothing uploaded
Keep this tab visible, close busy pages, then start a five-second or longer sample.
01
What the monitor refresh rate test checks
| Check | How it is measured | Fails when |
|---|---|---|
| Observed refresh rate | Animation-frame timestamps are converted into a median frame frequency in hertz. | Fewer than 60 valid frame intervals arrive before the test stops. |
| Estimated range | Median absolute deviation produces a lower and upper browser-observed range. | The range remains wide because frame delivery changes during the sample. |
| Run conditions | The page records sample duration, delayed frames and whether the tab became hidden. | The tab hides, power saving intervenes or background work disrupts the sample. |
How to run the monitor refresh rate test
- Select the monitor and refresh mode in system display settings. Put this browser window on that screen and keep the tab visible.
- Start the refresh rate test and collect at least five seconds of animation-frame intervals. Record the median Hz, range, delayed frames and sample count.
- If the value differs from the selected mode, repeat with the same window and power state, then change one display or browser condition.
If something failed
Keep the window visible and still. Background load, power saving and variable refresh can alter delivered animation frames. Repeat with one condition changed and compare sample counts.
Discard this run. Browsers may pause or throttle requestAnimationFrame in hidden tabs; keep the tab foreground and collect a fresh five-second sample.
02
How to read the result
Refresh rate test or FPS test?
A refresh rate test here reports how often this page received animation frames. It is not a game FPS benchmark or a monitor hardware certificate.
Is a 120hz test or 144hz test showing near 60 Hz? Check the system-selected mode and the display containing this window first. Then repeat the screen refresh rate test online with the tab visible and the same power state.
The monitor refresh rate tester reports a median and range from frame intervals. Game FPS, often written fps, is frames rendered by a particular game and can differ from this page's callback rate. The short monitor checklist covers other new-display checks.
How the monitor refresh rate test works
requestAnimationFrame timestamps are converted to intervals and a median frequency. The displayed range comes from variation in those intervals. A delayed-frame count flags unusually long intervals in this run.
Keep the tab foreground for at least five seconds. Fewer than 60 valid intervals or an earlier stop leaves too little evidence; a hidden tab invalidates the run.
Which screen holds the browser window? Move it deliberately before comparing a second display. Do not combine samples from different screens or power states.
What the result can establish
Monitor refresh rate test reports how this browser page ran during the sample. A stable value near the selected system mode does not confirm the panel's rated mode or every application's frame delivery.
If the estimate stays near 60 Hz while the system says 144 Hz, confirm the selected display and mode, then compare another browser with the same window position. A dock, cable, mirrored display or power mode can also affect the route.
Record median Hz, range, delayed frames and sample count. The fastest single interval is not the result. Repeat under fixed conditions before making a hardware claim.
Measurement limits
The page cannot read the monitor's EDID, cable bandwidth or panel timing. Its animation-frame sample is a browser observation, not a certification of 120 Hz or 144 Hz hardware.
Variable refresh, compositor scheduling, background load and power saving can change callback timing. A low or wide range calls for a controlled repeat, not a diagnosis of a defective panel.
A refresh rate test also cannot measure game FPS or input-to-photon delay. Use the operating system and display information for the selected mode, and test the original application separately.
03
Monitor refresh rate test questions
What does this monitor refresh rate tester measure?
The monitor refresh rate tester counts animation-frame intervals delivered to this visible page and reports a median Hz with a range. It cannot read the monitor's rated hardware mode.
Why can a 120hz test still show about 60 Hz?
A 120hz test can show about 60 Hz when the system mode, browser window's display, power setting or compositor limits callback delivery. Check one condition at a time and repeat a full sample.
Can a 144hz test prove that my monitor is running at 144 Hz?
No. A 144hz test near 144 Hz shows this page's callback frequency during the run. Check the selected system mode and monitor information separately; the screen refresh rate test online does not certify the panel.
What is the difference between refresh rate and FPS?
Refresh rate is how often a display is configured to update. FPS is how many frames an application renders. This page samples browser callbacks, so it cannot report a game's FPS or read the display's selected mode.
How should I repeat the monitor refresh rate test fairly?
Keep the tab visible on the same monitor for at least five seconds. Compare median Hz, range, delayed frames and sample count before changing one setting.
What can the monitor refresh rate test not prove?
The monitor refresh rate test cannot inspect panel hardware, cable capability or game performance. A stable browser sample is evidence for this page only.