Why does a refresh rate test fluctuate?

Browser scheduling, background activity, power saving, variable refresh rate and frame timing can cause small fluctuations. Use the long-term stable range rather than one sample.

Why does a 120Hz display show 119Hz?

Small differences can come from timing precision and the display clock. A stable result close to the selected mode is usually expected.

Is this browser result a hardware measurement?

No. It estimates animation-frame timing and cannot replace operating-system display information or dedicated measurement equipment.

Display test

Refresh Rate Test

Estimate monitor Hz from animation-frame timing. Browser limits, power saving and background tabs can affect the result.

Average Hz

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1% low Hz

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Sampled frames

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This is a browser estimate and does not replace dedicated measurement equipment.

How to measure refresh rate accurately

Connect the display with a cable and port that support the intended resolution and refresh rate.
Select the target mode in the operating system or device display settings.
Keep this tab visible, close heavy background work and disable battery-saving limits where appropriate.
Run the five-second measurement several times and compare the stable range rather than one peak value.
Confirm unexpected results in the operating-system display panel and with the manufacturer’s supported modes.

Refresh rate test FAQ

Why does the result fluctuate?

Browser scheduling, background activity, power saving, variable refresh rate and frame timing can create small changes. Compare several samples while the tab stays active.

Why does a 120Hz display show about 119Hz?

Timing precision and display-clock differences can produce a result slightly above or below the selected mode. A stable value close to 120Hz is normally more important than an exact integer.

Can a browser test prove the panel’s maximum refresh rate?

No. The test estimates the mode currently presented to the browser. Hardware capability also depends on the panel, GPU, port, cable, resolution and system settings.

Understand the result

A correct refresh-rate mode does not guarantee clear motion. Pixel response, overdrive and frame delivery also matter. Compare the motion blur test, read why browser refresh readings vary, or use the 60Hz vs 120Hz buying guide. If the higher mode is missing from your system settings, follow the monitor stuck at 60Hz checklist.