Screen Refresh Rate Test
UFO Test: measure your live refresh rate and frame rate.
Press start and watch how smoothly the little UFO flies — that is your refresh rate.
Why this tester
Intuitive UFO comparison
The UFO Test is the classic subjective refresh-rate check: a little saucer glides across the screen and your eyes judge the smoothness instantly — no expertise required.
Three speeds on one screen
Full, 1/2 and 1/4 rate UFOs fly together, so the stutter of low rates and the glide of high rates can be compared directly, side by side.
Live data panel
A rAF frame counter reports the current rate, peak rate and stability percentage live, plus automatic resolution, GPU and OS detection.
Install-free, cross-platform
Built on native browser APIs — runs on Windows, macOS, Android and iOS out of the box, with black/white backgrounds and an immersive mode that works even on iPhones.
How the UFO Test works
- 01 · Start the test
Press Start and watch the little UFO glide across the screen; enable the 1/2 and 1/4 rate simulations to compare high vs low refresh rates side by side.
- 02 · Judge smoothness
The smoother the UFO flies, the higher your refresh rate. Visible stutter, jumping or ghosting points to a low rate or slow pixel response.
- 03 · Read the data and adjust
The page shows the live rate, peak rate and stability; set your display to its highest supported refresh rate in system settings for the best experience.
Refresh rate & FPS explained
- Refresh rate
- How many times per second the display redraws, in hertz. 60Hz means at most 60 redraws per second — the ceiling of visual smoothness.
- FPS
- Frames per second output by the GPU. Even at 200 FPS, a 60Hz panel only shows 60 of them — the lower of the two wins.
- UFO Test
- The classic subjective refresh-rate check: a UFO glides across the screen and your eyes judge the smoothness, with 1/2 and 1/4 rate comparisons to make the difference obvious.
- What rate is good?
- 60Hz is the baseline; 75–144Hz is great for daily use; above 144Hz is aimed at gamers, with a clear jump in responsiveness.
- Response time (GtG)
- How long a pixel takes to switch between gray levels, in milliseconds. Slow response causes ghosting — even at a high refresh rate — and is an independent metric.
- Overdrive
- A monitor feature that drives liquid-crystal pixels to change faster. Too low keeps the ghosting; too high causes overshoot artifacts — the "medium" preset is usually the sweet spot.
Troubleshooting guide
Stuck at 60Hz on a high-refresh panel
Symptom: the monitor is 144Hz/165Hz but the page reads 60Hz.
How to fix it:
- Open system display settings → advanced display and manually set the highest refresh rate (Windows often defaults to 60Hz).
- Check the cable: HDMI 1.4 cannot carry 144Hz — use DP 1.4 or HDMI 2.1.
- Update GPU drivers (NVIDIA/AMD/Intel); old drivers may not expose high-refresh modes.
- On laptops, enable discrete-GPU direct output — hybrid mode may lock the panel to a low rate.
Heavy UFO ghosting
Symptom: the saucer drags long colored trails.
How to fix it:
- Set the monitor OSD Overdrive / response time to "medium" (too high causes overshoot artifacts).
- Check strobing features (ELMB/ULMB) — they are mutually exclusive with high refresh; pick one.
- Some VA panels are inherently slow; consider IPS / Fast-IPS if it bothers you.
Unstable readings
Symptom: the rate jumps around and stability sits well below 100%.
How to fix it:
- Close other tabs and background heavy apps (downloads, video encodes).
- Plug the laptop in — battery mode throttles rendering; on phones disable power saving.
- Retest in a Chromium browser (Chrome / Edge) to avoid engine throttling.
Refresh rate optimization tips
Set it in the system
Windows: Settings → Display → Advanced → refresh rate; macOS: System Settings → Displays. Always double-check after connecting a new monitor.
Cables and ports
High refresh needs bandwidth: DP 1.4 does 4K@144Hz, HDMI 2.1 does 4K@120Hz+. A cheap or legacy cable is the most common cause of a locked 60Hz.
Keep drivers fresh
GPU driver and monitor firmware updates often unlock new high-refresh modes; the NVIDIA/AMD control panels also allow per-app refresh overrides.
In-game sync
Enable G-Sync / FreeSync in games and cap the frame rate at the refresh rate to eliminate both tearing and stutter.
Phone prep
Disable power saving and close heavy background apps before testing; iPhones may cap web pages at 60Hz — trust the rate stated in system settings.
Frequently asked questions
What is a refresh-rate comparison test?
It simulates lower refresh rates so you can see the difference directly: the 1/2 and 1/4 rate UFOs visibly jump and stutter, showing exactly what refresh rate does to the experience.
Why is my result unstable?
Assuming hardware and cabling are fine, system load and browser performance can skew it. If a professional tool disagrees, trust the professional tool.
How do I raise my refresh rate?
Change it in system display settings, keep GPU drivers up to date, and use a high-refresh panel with a capable cable (DP 1.4 / HDMI 2.1).
Is some ghosting normal?
Slight ghosting is normal. Heavy trails suggest a low refresh rate or slow pixel response — try enabling the monitor’s Overdrive setting.
Does it work on phones?
Yes — the tool runs on Windows, macOS, Android and iOS, though some mobile browsers cap the frame rate; cross-check with the rate stated in system settings.
Does the browser matter?
Yes. Rendering engines differ; use a modern browser like Chrome or Edge with power saving and heavy background apps off.