Monitor Refresh Rate Test

Estimate the frame cadence your browser is currently presenting.

The test samples requestAnimationFrame timestamps while this tab is visible. It estimates browser presentation cadence, not the monitor signal itself.

The test samples requestAnimationFrame timestamps while this tab is visible. It estimates browser presentation cadence, not the monitor signal itself.

Preparing measurement

Live browser estimate

Hz
0.0 Hz

Based on the recent median animation-frame interval.

Stable estimate

Hz
– Hz

Keep the tab visible while a stable sample is collected.

Frame-timing consistency

0%

Share of recent frames within 10% of the median interval; this is not a monitor quality score.

Frames sampled

0

Visible measurement time

0.0 s

Median frame interval

–

What this tool does

This tool estimates the cadence of visible browser animation frames from requestAnimationFrame timestamps.

It reports a live estimate, a stable estimate, median frame time, and recent frame-timing consistency.

How to use the tool

  1. Keep this tab visible and avoid moving it between monitors during the measurement.
  2. Wait for the stable estimate or review the live value and consistency indicator.
  3. Pause the measurement when needed; resuming excludes the paused interval.
  4. Restart after changing the display mode, refresh-rate setting, browser, or monitor.

Useful applications

  • Checking whether a browser appears to run near 60, 120, 144, 165, 240 Hz, or another configured rate.
  • Comparing browser behavior before and after changing an operating-system display setting.
  • Observing frame-timing stability under different power, load, or multi-monitor conditions.
  • Diagnosing why web animations appear capped or uneven.

Notes and limitations

  • requestAnimationFrame normally follows the browser's presentation schedule, which often tracks the active display but can be capped or throttled.
  • Background tabs are commonly paused or throttled, so the test automatically pauses while the document is hidden.
  • Dropped frames, variable refresh rate, browser compositing, system load, power saving, remote desktops, and multiple monitors can affect the estimate.
  • The tool cannot directly read the monitor's electrical signal or guarantee its configured hardware refresh rate.

Frequently asked questions

Does this read the monitor's exact hardware refresh rate?

No. It estimates visible browser frame cadence from animation timestamps. Browser, compositor, and operating-system behavior can differ from the panel signal.

Why does it show 59.9 instead of 60 Hz?

Many display modes use fractional rates such as 59.94 Hz, and normal timing variation can also shift the estimate slightly.

Why is the value lower than my monitor setting?

The browser may be capped, the page may be on another monitor, frames may be dropped, or power-saving and system load may reduce callback cadence.

What does frame-timing consistency mean?

It is the percentage of recent frame intervals that stay within 10% of their median. It describes the browser sample, not overall monitor quality.

Is any measurement data uploaded?

No. Timing samples are processed in your browser and are not sent by this tool.

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