TrueScreenTest

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Refresh Rate Test

Check whether your 120 Hz, 144 Hz or 240 Hz display is really running at that speed. The reading below updates live as your browser draws each frame.

Refresh rate

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Measuring. Keep this tab in front and the mouse still.

Median frame time
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Frame time range
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Steady frames
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Long frames (last 240)
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Screen size
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Physical pixels
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Pixel ratio
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How to use

How to use the refresh rate test

  1. Leave the page in front for a couple of seconds. Measuring starts on its own; keep the mouse still while it settles.
  2. Read the big number. It is the refresh rate your browser is drawing at, rounded to a standard value like 60, 120 or 144 Hz when it is close.
  3. Watch the graph. Even yellow bars mean steady frames. Red bars are frames that took too long.
  4. Check the strip at the bottom: the yellow square steps once per frame, the blue one glides. Skips or stutters mean dropped frames.
  5. Changed a setting? Press Measure again to start a fresh reading.

Controls

Refresh rate
Frames per second your browser is drawing.
Median frame time
Typical time between frames.
Steady frames
Share of frames close to the median.
Long frames
Frames that took 1.5× longer than normal, out of the last 240.
Measure again
Clears the history and starts over.

In-depth guide: Monitor stuck at 60 Hz?

How it works

What the number means

Browsers draw a new frame each time the display refreshes. This test times every frame with requestAnimationFrame and reports the typical gap between frames as a refresh rate. A 60 Hz screen draws a frame every 16.7 ms, 120 Hz every 8.3 ms and 144 Hz every 6.9 ms.

The yellow square in the strip under the readout moves one step per frame; the blue one moves at a steady speed. If the yellow square skips or the blue one stutters, frames are being dropped.

Troubleshooting

Seeing 60 Hz on a faster screen?

  1. Check the display setting. On Windows go to Settings › System › Display › Advanced display and pick the highest refresh rate. On a Mac open System Settings › Displays. On Android look under Display › Motion smoothness or Refresh rate.
  2. Check the cable and port. Older HDMI cables and ports can limit high resolutions to 60 Hz. DisplayPort or an HDMI 2.1 cable usually fixes this.
  3. Turn off power saving. Laptops on battery, Low Power Mode on iPhone and battery saver on Android often cap the rate at 60 Hz.
  4. Move the window. With several monitors, the browser follows the screen the window is on. Drag it to the fast monitor and press Measure again.

Limits

Limitations

  • This measures how often the browser draws, which normally matches the display. Browsers can draw less often when busy, in background tabs or in power-saving modes, so the result can be lower than what the monitor supports.
  • With variable refresh (G-Sync, FreeSync, ProMotion, adaptive sync), the rate changes with content, so readings can move around or land between standard values.
  • Some browsers limit web pages to 60 Hz on certain devices even when the screen is faster. Safari on iPhone has done this unless a developer setting is changed.
  • It can’t measure response time, input lag or overdrive. For motion clarity, try the ghosting test.

FAQ

Questions

Is refresh rate the same as FPS?

Not quite. Refresh rate is how many times per second the screen updates. Frames per second is how many new images a game or app produces. In a browser with nothing heavy running, the two usually match, which is why this test can estimate the refresh rate.

Why does the number change slightly?

Frame timing always has a little jitter. The test uses the median of the last 240 frames and rounds to a standard rate when it is within 3%, so small changes are normal.

What is the screen size shown here?

Screen size is the resolution your browser reports in CSS pixels. Physical pixels multiplies that by the pixel ratio, which on most systems matches the panel’s native resolution when scaling is applied.

Test kit

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