Refresh rate test
How many times a second your screen really updates.
Refresh rate
…Hz
Measuring… keep this tab in front.
- Measured
- –
- Frame time
- –
- Jitter
- –
- Frames per second now
- –
- Dropped frames
- –
Moving test
Speed
The ball should glide evenly, with its trail equally spaced. Uneven gaps or jumps mean frames were dropped.
FramesEach mark is one frame. Red marks are frames that were missed.
- Browsers run animations no faster than the screen, and may run slower on battery saver, in a background tab, or with variable refresh (adaptive sync).
- With several screens, the result is for the screen the window is on.
- Phones with adaptive refresh may lower the rate when nothing moves, so something keeps moving during the measurement.
Nothing leaves your device
This tool runs entirely in your browser. What you type, play or record here stays on your device: nothing is uploaded or saved on a server.
Example
Example: what the test shows on 60, 120, 144 and 165 Hz screens
The page times about three seconds of frames. The big number is the measured rate rounded to the usual rate it is within 2 % of; the Measured box keeps the exact figure, and Frame time is one frame in milliseconds.
- A browser that rounds its time stamps to whole milliseconds gives gaps of 16 and 17 ms on a 60 Hz screen: still read as 60 Hz, with a jitter of about ± 0.47 ms.
- On a 144 Hz monitor, three frames missed in the three seconds show as Dropped frames 3, and as red marks on the frame strip.
| Measured | Shown | Frame time |
|---|---|---|
| 59.94 Hz | 60 Hz | 16.68 ms |
| 74.97 Hz | 75 Hz | 13.34 ms |
| 119.88 Hz | 120 Hz | 8.34 ms |
| 143.86 Hz | 144 Hz | 6.95 ms |
| 164.80 Hz | 165 Hz | 6.07 ms |
| 239.76 Hz | 240 Hz | 4.17 ms |
| 110.00 Hz | 110.0 Hz, not a usual rate | 9.09 ms |
A monitor sold as 144 Hz should show 144. If it shows 60, the screen is set to 60 Hz in the display settings or the cable can’t carry more: change it and press Measure again.
How it works
- Open the page and keep it in front for three seconds while it measures.
- Read the refresh rate — rounded to the usual 60, 120, 144 Hz when it matches — with the frame time and jitter.
- Watch the moving ball and the frame strip: an even trail means smooth frames, red marks mean dropped ones.
Frequently asked questions
- How is the refresh rate measured?
- From the times the browser draws each frame over about three seconds: the typical frame interval gives the rate — 16.7 ms is 60 Hz, 8.3 ms is 120 Hz, 6.9 ms is 144 Hz.
- My monitor is 144 Hz but the test says 60 — why?
- The screen may be set to 60 Hz in the system’s display settings, the cable or port may not carry the higher rate, or battery saving may cap it. Change the setting and measure again.
- What are dropped frames?
- Frames the computer didn’t finish in time, so the screen showed the previous one again. A few are normal; many mean the device is busy or the browser is throttled.
- Does it work on phones?
- Yes. Phones with adaptive refresh lower the rate when nothing moves, so the page keeps something moving while it measures.
- Why does the Measured box say 59.94 Hz and not 60?
- Many screens run a fraction under their nominal rate; 59.94 Hz is common on TVs and laptops. Anything within 2 % of a usual rate, from 24 to 360 Hz, is shown as that rate in the big number, and the exact figure stays in Measured.
- What does jitter mean?
- How unevenly the frames arrive: the spread of the gaps between them, in milliseconds. A browser that rounds its timing to whole milliseconds gives about ± 0.47 ms at 60 Hz on its own, so a figure that small means even frames.
- Is anything sent anywhere?
- No. It is measured in your browser.
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