Measure your real frame rate, not just a live counter
This FPS test samples the exact time between every screen paint using the browser's high-resolution requestAnimationFrame timer, then turns those samples into the metrics that actually describe smoothness: average FPS, 1% and 0.1% lows, peak and minimum FPS, a frame-time-consistency stability score, and a count of janky frames. It's the quickest no-install way to sanity-check a device, browser, monitor, or extension setup against choppy animation.
Why 1% lows matter more than average FPS
A display can average a healthy 60 FPS and still feel stuttery because a handful of slow frames break the illusion of motion. That's what the 1% low and 0.1% low capture — the frame rate during your worst 1% and 0.1% of frames. Big gaps between your average and your 1% low point straight at stutter sources: a background tab, a heavy extension, thermal throttling, or hardware acceleration being switched off.
Put your hardware under real load
Switch on the render stress stage and the tool animates hundreds to thousands of moving objects on a canvas while it measures — genuine GPU and compositor work, not a fake number. Watch how far your FPS drops and how quickly your 1% low collapses under Light, Medium, and Heavy load to gauge real-world headroom before your browser starts dropping frames.
Benchmark, grade, and beat your best
Run a fixed 10, 30, or 60-second benchmark or leave it running continuously. Each timed run ends with a performance grade — from Struggling to Flawless — scored against your detected display refresh rate, and your best average for each duration is saved locally on your device so you can compare browsers, tabs, and settings over time.
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- High-Resolution Sampling: Uses the native requestAnimationFrame timer to record the exact millisecond frame-time of every screen paint.
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- Pro Frametime Metrics: Average FPS plus true 1% and 0.1% lows (the worst 1% / 0.1% of frames) — the numbers that reveal stutter.
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- Frame-Time Stability Score: A consistency rating from frame-time variance, so you can tell steady motion from a bursty, janky feel.
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- Adjustable Render Stress: Animate 250–5,000 moving canvas objects to put real GPU and compositor load on your hardware and watch FPS react.
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- Timed Benchmarks + Grade: Run 10s, 30s or 60s tests (or continuous) and get a Struggling-to-Flawless grade scored against your display.
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- Refresh-Rate Detection: Auto-detects your monitor's Hz so it knows the target frame rate and can flag dropped frames.
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- Live Chart with Reference Lines: Real-time FPS graph marked at 30, 60, 120, 144 and 240 FPS for instant context.
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- Personal Best + Fullscreen: Your best average for each duration is saved locally, and a fullscreen mode gives a clean, distraction-free readout.
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- Privacy-First: Every metric is computed in your browser — nothing is uploaded, no account, no ads in the way.
