Measures the actual refresh rate of your browser/display via requestAnimationFrame timing.
Detects ghosting and persistence with a high-contrast moving bar. Works on any device.
requestAnimationFrame to the display refresh rate.
A monitor at 60 Hz reports ~60 fps; 120/144/240 Hz monitors show their actual rate. Inside VR, you'll see your headset's refresh rate. Run for 5+ seconds for a stable measurement.