IdleTab

Refresh Rate Test

This page counts the frames your browser paints and turns the time between them into a rate in hertz. It measures what is reaching the screen right now, which is not always the highest rate the panel can run at.

Live refresh rate

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Collecting frames. Keep this tab in front for a few seconds.

Frames measured
0
Closest common rate
This does not sit close to any common refresh rate.

Smoothness

The marker below moves one step per frame. An even glide means the frames arrive evenly. A visible stutter is a frame that came late, or never came at all.

Full rate against 30 fps

See the difference between full rate and 30 fps on your own screen. All three markers cross the track in the same time. The first moves on every frame, the second on every other frame, and the third is held near 30 frames per second at whatever rate this browser is drawing.

Every frame

Every second frame

About 30 frames per second

On a 60 Hz display the first two lanes look almost alike, because half of 60 is already close to 30. The gap between them opens up on a screen running faster than that.

How to get a reading you can trust

  1. Leave this tab in front and stop moving the mouse. Anything else the browser has to draw competes with the measurement.
  2. Wait about five seconds. The first frames after a page loads are irregular, so they are thrown away.
  3. Close heavy tabs and pause anything playing video. A loaded machine drops frames, and the test then reports the drop rather than the panel.
  4. On a laptop, plug it in first. Battery saving lowers the frame rate on purpose.

What this number can and cannot tell you

This is a browser measurement, so read it as what the browser is drawing right now. Five things move that number for reasons that have nothing to do with the panel.

  • The browser reports what it renders, not what the panel can do. A monitor sold as 165 Hz still reads 60 here if anything between the two is holding the frame rate down.
  • Power saving caps it. On battery, in a low power mode, or on a machine that has grown warm, the system lowers the frame rate deliberately. Plug in, switch low power mode off, and measure again.
  • Some browsers stay at 60 until high refresh is switched on. Browsers have shipped with the animation clock pinned to 60 Hz, and then the page cannot see anything faster whatever the display is set to.
  • A background tab stops rendering. Browsers slow down or fully stop animation frames in a tab you cannot see, so a reading only means something while this tab is in front.
  • A variable refresh display is meant to show a range. On a screen running FreeSync, G-SYNC or ProMotion the refresh rate follows the content, so a spread of values is the display doing its job.

Refresh rate and frame rate are not the same thing

The refresh rate is how often the display redraws itself, and the panel and the operating system set it. The frame rate is how often something new is ready to be drawn. This test measures the second one, because the second one is all the browser gets to see. When the machine has frames to spare the two match, and that is when the reading is worth something.

Frequently asked questions

Why does my 144 Hz monitor show 60 here?

Usually because something is capping the browser rather than the monitor. The common causes are a display still set to 60 Hz in the operating system, a laptop running on battery, a browser whose animation clock is fixed at 60 Hz, and a window sitting on a second screen that runs slower. Check the display settings first, then drag the window onto the fast screen and measure again.

Is this my monitor's maximum refresh rate?

No. It is the rate the browser is drawing at while you watch, and that can only be equal to or lower than what the panel supports. A high reading proves the whole chain can reach that rate. A low reading is a reason to look at the settings, not a verdict on the hardware.

Why does the number jump around?

Either the machine is busy or the display is variable. A busy machine misses frames, and the gaps between them stop being even. A variable refresh display changes its rate on purpose to match the content, so a range is correct behavior there. The steady or uneven line under the reading tells you which case you are in.

Does this work on a phone?

Yes, and the caveats matter more there. Phones and tablets change refresh rate constantly to save battery, and many high refresh screens drop to 60 Hz or lower as soon as nothing on screen is moving. A reading taken on a still page with a low battery describes the power mode, not the panel.

The other screen tests