Live frame rate measurement via the browser's rAF clock. Reports current FPS, average, min, max, and 1% low — plus detects whether your display runs at 60, 120, 144, 165 or 240 Hz.
FPS Test is a free, browser-based screen testing tool that lets you measures browser frame rate live using requestAnimationFrame.
This tool uses the browser's requestAnimationFrame callback, which fires once per display refresh. By measuring the time between consecutive callbacks we derive the frames-per-second rate the browser is actually achieving on your device. The result is capped by two things: your monitor's refresh rate (since rAF can't fire faster than the display can update) and any throttling your browser applies (background tabs, power saving, GPU pressure).
Raw FPS numbers fluctuate frame-to-frame, so the meaningful metrics are the averages across a sustained run. "Average" is the smoothed mean of every half-second of rendering. "1% low" is the slowest 1% of frames — this is the number that actually feels like stuttering when gaming or scrolling. A perfect 60 Hz setup shows 60 average / 60 min / 60 max / 60 1%-low. A stuttery setup might show 60 average but 38 for 1%-low, which will feel choppy even though the average is high.
The max FPS over a sustained run is effectively your display refresh rate (as the browser sees it). Common values:
If you expected 144 Hz and see 60 Hz, check Windows Display Settings → Advanced → Refresh rate, and make sure your monitor is plugged into a DisplayPort or HDMI 2.0+ cable with enough bandwidth.
Chrome, Firefox, and Edge all throttle background tabs to save battery and CPU. A tab not in the foreground typically drops to 1 Hz (one frame per second) or suspends rendering entirely. For an accurate reading, keep this tab focused and your browser window in the foreground. Also close other heavy tabs — if another tab is doing GPU work it can steal frames from this one.
If the FPS average looks stable but motion still jumps forward, use the frame skipping test and the frame skipping guide to separate browser frame pacing from physical monitor refresh gaps.
FPS Test FAQ
