Refresh rate test. The Hz the screen is really at.
Ten seconds of frames are timed to find the rate your screen runs at, to two decimals, with how sure the count is. Tell it what the panel is sold as and, if it is running lower, it names why: the settings, battery power, a second monitor, the browser.
One check
- Refresh rate
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
In short
Refresh rate test: the answer first
A refresh rate test times ten seconds of frames to find the rate your screen is really running at, to two decimals, with how sure the count is. If it is below what the panel is sold as, the page names the cause it saw.
Reading your result
- Read the confidence beside the rate
- It grows with the frames timed and falls when they arrive unevenly. A low confidence means run it again with the tab in front.
- 60 on a faster panel
- Usually the display settings, battery power, or a second monitor at a lower rate. The cause is named only when the page saw it.
- A late frame cannot pull it
- The rate comes from the densest run of intervals, so an occasional slow frame does not lower it. Uneven frames are the pacing test's job.
What it measures
Measured here, not assumed.
- Refresh rate
- The rate read from the densest run of frame intervals, to two decimals, and the panel rate it matches. A late frame cannot pull it.
- Confidence
- How sure the count is: it grows with the frames timed and shrinks when they arrive unevenly.
- The cause
- When the rate is below the rating: the display settings, battery power, a software renderer, Safari's 60 fps preference, or two monitors at different rates, named only when the page saw it.
If it fails
The usual failures, and what fixes each.
- 60 Hz on a high refresh monitor
- Set the refresh rate in the system's display settings and, on a PC, in the graphics driver's panel; the path for your device is shown under the fixes on this page. Use DisplayPort or an HDMI cable rated for the rate.
- Frames dropped
- Close other tabs and programs. On a laptop, plug in; battery mode caps the graphics chip.
- Too few frames counted
- Keep the tab in front and the window still while it runs.
Where a browser stops
What it cannot tell you.
- Variable refresh rate. G-Sync and FreeSync change the rate with content; this measures the fixed rate the browser sees.
- The panel's true maximum if the system is set lower. It measures what is running, which is the point.
- Response time and ghosting.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Refresh rate test, answered
- How do I check what refresh rate my monitor is running at?
- Run the test above with the tab in front. It times frames for five seconds and reports the rate, such as 60, 120 or 144 Hz.
- Why does my 144 Hz monitor show 60 Hz?
- Because the system is set to 60. Change it in the display settings and the graphics driver's control panel, and check the cable supports the rate.
- Does the browser limit the reading?
- Browsers draw at the screen's rate, so the reading normally matches the panel. A browser that cannot keep up shows as late frames, and the verdict says the count is not sure rather than reporting a lower rate as the panel's.
- My 144 Hz monitor reads 60. What do I change?
- Set the rate in the system's display settings and, on a PC, the graphics driver's panel, and use DisplayPort or an HDMI cable rated for it.
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