ScreenBGScreenBG
…Hz
Measuring — keep this tab in front…
Frames last second
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Jitter
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Dropped (2 s)
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Dropped total
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Frame time · last 240 frames (red = dropped)
Motion check · the dot should glide with no hitches; one cell lights per refresh

Refresh Rate Test

Free refresh rate test: measures the Hz your browser is really drawing at, plus frame time, jitter, and dropped frames, live. Check that a 144 Hz or 240 Hz monitor isn't stuck at 60 Hz, see a frame-time graph that exposes stutter, and get a clear verdict with the exact fix when the measured rate doesn't match your monitor. Works on any monitor, phone, or TV browser with no install.

What you can use it for

  • Confirm a new 144/165/240 Hz monitor is really running at its rated refresh
  • Catch a cable, port, or Windows setting that silently caps you at 60 Hz
  • Spot stutter and dropped frames before blaming a game
  • Check a phone's 90/120 Hz mode or a laptop on battery saver

How to check your monitor's refresh rate

  1. Open the test and keep the tab in front; it measures for a couple of seconds.
  2. Read the big number: the refresh rate your browser is actually drawing at, named after the nearest real rate (60, 120, 144, 165, 240 Hz…). The precise measured value is underneath.
  3. Check the verdict and the dropped-frame counters. Steady pacing with no drops means the display link is healthy.
  4. Moved the window to another monitor? Press Restart measurement.

Your 144 Hz monitor shows 60 Hz? How to fix it

  • Windows: Settings › System › Display › Advanced display › Choose a refresh rate, then pick the highest value.
  • Cable and port: use DisplayPort, or HDMI 2.0/2.1 for high refresh rates at 1440p and 4K, and plug into the graphics card rather than the motherboard.
  • NVIDIA / AMD: check the refresh rate in NVIDIA Control Panel › Change resolution, or AMD Software › Display.
  • Mac: System Settings › Displays › Refresh rate, then choose ProMotion or the highest option.
  • Laptops and phones: battery saver and low power mode often cap browsers at 60 Hz or even 30 Hz. Plug in and turn them off.

What dropped frames and jitter mean

A dropped frame is a refresh where the browser didn't deliver a new image, so motion stutters even when the refresh rate is right. Jitter is how much frame times vary; a few hundredths of a millisecond is excellent. Regular drops with nothing else running usually point to a busy CPU or GPU, too many tabs, or browser hardware acceleration being turned off.

Next: test motion clarity

Once the refresh rate is right, run the monitor ghosting test to see how cleanly fast motion is drawn, and the dead pixel test to check the panel itself.

Frequently asked questions

How does a browser measure refresh rate?+

Browsers draw one animation frame per display refresh. The test times thousands of frames and uses the median interval, so one slow frame doesn't skew the result.

Why does it show 60 Hz on my 144 Hz monitor?+

Usually Windows is set to 60 Hz (Settings › Display › Advanced display), the cable or port can't carry the higher rate (use DisplayPort or HDMI 2.1), or a battery saver is capping the browser. Fix it, reload, and measure again.

What are dropped frames?+

A frame that takes noticeably longer than one refresh interval. A few during page load are normal; regular drops while nothing else is running point to a busy CPU or GPU, a background tab, or a browser limit.

Does it detect G-Sync or FreeSync?+

Not directly. Variable refresh rate mostly matters in games; browsers usually draw at the fixed maximum refresh, so this test reports that maximum.

More screen tests

Dead Pixel Test

Cycle full-screen colors to find dead and stuck pixels fast.

Screen Uniformity Test

Check brightness and color evenness across the whole panel.

Monitor Ghosting Test

Frame-locked moving objects to spot ghosting, smearing, and overshoot.

Touch Screen Test

Swipe to find dead zones and count simultaneous touch points.

Backlight Bleed Test

Pure black screen with corner markers to spot edge light leak.

Color Banding Test

Exact 8-bit gradient ramps to reveal banding, tints, and crushed shadows.

Contrast Test

Shaded squares to calibrate black levels and white clipping.

Resolution Test

Live readout of native resolution, scaling, refresh rate, HDR, and viewport.

Text Sharpness Test

Tiny text samples to judge subpixel rendering and clarity.

Overscan Test

A 1-pixel grid and corner circles to fix overscan and cropping.