Stutter Test
Late and dropped frames are counted while the graph runs.
Frame stats
- Current FPS
- --
- Average FPS
- --
- Min / Max
- -- / --
- 1% low
- --
Display
- Refresh rate (est.)
- -- Hz
- Frame interval
- -- ms
- Stability
- Measuring
- Screen
- --
Motion test
3 speedsShortcuts
- Space pause
- R reset stats
- F fullscreen
This stutter test watches every frame interval. Any frame that takes more than 1.5 times the usual interval (and at least 4 ms longer) counts as late, and the number of refreshes it covered is added to the dropped counter.
What the stutter test counts
Late frames
Frames that arrived noticeably later than the normal interval.
Dropped frames
Estimated refreshes that were skipped while a late frame was waiting.
Stability
Smooth: under 1% late in the last 240 frames. Minor stutter: under 5%. Stuttering: 5% or more.
Common causes of stutter
Check the display setting
Windows: Settings → System → Display → Advanced display. macOS: System Settings → Displays. Pick the highest refresh rate your screen offers.
Use a performance power mode
Laptops and phones often limit frame rate on battery. Plug in or switch to a high performance profile, and turn off low power mode.
Update graphics drivers
Install the latest driver from NVIDIA, AMD or Intel, or update your phone and browser.
Turn on hardware acceleration
In Chrome or Edge, enable “Use graphics acceleration when available” and restart the browser.
Close heavy apps and tabs
Background apps, video calls and many tabs compete for the same graphics chip.
Use the right cable and port
High refresh rates need DisplayPort or a recent HDMI version, and the port on the graphics card, not the motherboard.
Frame time and refresh rates
| Refresh rate | Time per frame | Typical devices |
|---|---|---|
| 30 Hz | 33.3 ms | Some TVs and low-power modes |
| 60 Hz | 16.7 ms | Most office monitors, laptops, older phones |
| 90 Hz | 11.1 ms | Some Android phones, VR headsets |
| 120 Hz | 8.3 ms | Modern phones, iPad Pro, TVs, consoles |
| 144 Hz | 6.9 ms | Gaming monitors |
| 165 Hz | 6.1 ms | Gaming laptops and monitors |
| 240 Hz | 4.2 ms | Esports monitors |
Limits
This page measures what your browser actually draws, using requestAnimationFrame. Browsers cap their frame rate at the refresh rate of the display, so the Hz value is an estimate of the rate your screen is running at right now, not the maximum it supports. It cannot measure response time (GtG), input lag, screen tearing or whether the panel itself skips frames; those need special hardware or a camera.
Stutter FAQ
Is stutter the same as low FPS?
No. You can have a high average FPS and still stutter if some frames take much longer than others.
Can it detect screen tearing?
No. Tearing happens on the display and is not visible to the browser. Use the UFO motion test and look for a horizontal split.