Monitor Refresh Rate Test
Measure your display's active refresh rate in hertz (Hz) by tracking a moving UFO across the screen and timing the exact spacing between browser animation frames.
Ready
How it works
Web browsers synchronize visual updates with your display's refresh cycle using a standard programming interface called requestAnimationFrame. Every time your screen is ready to draw a new image, the browser triggers a callback and advances the animated UFO across the test area. By recording the high-resolution timestamps of these consecutive callbacks, this tool calculates the time gap between individual frames in milliseconds. It then divides one second by the average frame interval to estimate your current refresh rate in hertz (Hz), reflecting the actual update speed your browser receives.
Steps
First, close heavy background applications or video streams and move this browser window onto the specific monitor you want to check. Second, start or observe the test as the UFO moves smoothly across the screen while the tool collects frame timing intervals. Third, wait a few seconds for the frame spacing average to stabilize, then read your estimated refresh rate in Hz along with the frame interval measurements.
Controls
The live Hz readout shows the estimated refresh rate calculated from recent animation frames, while the frame time indicates the average milliseconds elapsed between each screen redraw. The moving UFO provides a visual reference so you can see motion smoothness and spot any stutters or dropped frames. Action buttons allow you to start, pause, or reset the timing sample if you switch display modes or move the window.
Examples
For example, if the tool records a steady frame spacing of about 16.67 milliseconds, it will report an estimated refresh rate around 60 Hz, which is typical for standard office displays. If the average spacing drops to roughly 6.94 milliseconds per frame, the readout will settle near 144 Hz. However, if a 144 Hz monitor still shows 60 Hz here, your operating system display settings or browser frame rate cap may still be limiting the output.
How to read your result
Treat the number shown as the effective refresh rate delivered to your web browser rather than a hardware diagnostic of the physical panel itself. Because the measurement relies on browser animation callbacks, it reflects your current operating system settings, cable bandwidth, power-saving modes, and browser compositing rules. A steady reading that matches your display specifications confirms that high-refresh output is active in your browser, while a lower or fluctuating number usually points to a configuration limit or background system load.
Reference ranges
These rough comparison bands are commonly cited hardware categories for general context and are not a medical, psychological, or clinical scale. Many standard office monitors, laptops, and older tablets land around 60 Hz (about 16.7 ms per frame). Mid-range productivity displays and many modern smartphones often operate around 75 Hz to 120 Hz (roughly 13.3 ms to 8.3 ms per frame). Dedicated gaming monitors commonly run around 144 Hz, 165 Hz, or 240 Hz and above, where frame spacing drops to about 6.9 ms or less.
Tips
On a desktop, plug laptops into wall power, close other browser tabs playing video, and verify that hardware acceleration is enabled in your browser settings. If you use multiple monitors with different refresh rates, keep the browser window entirely on one screen during the run. On a phone or tablet, turn off low-power or battery-saver modes, and touch or scroll gently if your device uses adaptive refresh rates that drop when idle.
FAQ
What does this test measure and what does it not claim?
This tool measures the timing interval between requestAnimationFrame callbacks in your browser to estimate your screen's active refresh rate in Hz. It does not measure pixel response time (GTG), input lag, color accuracy, or physical panel defects, and it cannot verify maximum hardware capabilities if your system settings cap the rate.
Why can two runs on the same device show different numbers?
Browser frame timing can fluctuate if background tabs, system notifications, or heavy CPU and GPU tasks briefly delay a frame callback. In addition, laptops switching to battery power, monitors with variable refresh rate features, or moving the browser window between two different screens can change the reported Hz between runs.
How do I run this test accurately on a phone or tablet?
Open this page in your mobile browser with battery saver turned off, as power-saving modes usually lock mobile screens to 60 Hz. Note that some mobile browsers and operating systems cap web page animations at 60 Hz even when the physical screen supports 90 Hz or 120 Hz in native apps.
Where are my test results stored and is anything uploaded?
All frame timing calculations happen entirely inside your browser on this device, and nothing is collected or uploaded to any server. Any saved history or high records are kept only in local storage on your own device, which you can clear at any time through your browser settings.
What do a high result and a low result usually mean here?
A higher Hz number simply means your display and browser are redrawing the moving UFO more times per second, resulting in smaller time gaps between frames. A lower number means fewer redraws per second, often due to a 60 Hz display setting, a power-saving cap, or dropped frames from system load.
Privacy
All measurements run locally in your browser on this device; no test results are collected or uploaded, though local storage may keep your records.