Monitor Refresh Rate Test (Hz Checker)
Measure your monitor's real refresh rate with high-precision frame timing, watch a moving UFO for motion smoothness, and check frame stability — all directly in your browser.
# Screen Refresh Rate (Hz) Explained: Input Lag & Motion Clarity
Refresh rate is how many times per second your monitor redraws the image on screen. A 60Hz display redraws every ~16.67ms; a 240Hz display redraws every ~4.16ms. Every extra redraw per second means the image you see is a more recent snapshot of the game state, which is why higher refresh rates feel more responsive even when your reaction time itself hasn't changed.
Motion clarity
Fast-moving objects on a low refresh rate display appear blurrier because each frame stays on screen longer relative to how far the object moved. Higher refresh rates shorten that per-frame display time, producing a crisper, less smeared trail — which is exactly what the moving UFO visualizer above is designed to make visible.
Input lag
Part of the delay between moving your mouse and seeing the result on screen comes from waiting for the next available frame to be drawn. At 60Hz that wait can be up to ~16.67ms; at 360Hz it drops to under 3ms — a meaningful reduction for fast-paced competitive games.
# Display Connection & Cable Guide
- HDMI 2.0: supports up to 1080p at 240Hz or 4K at 60Hz — a common bottleneck for 4K high-refresh setups.
- HDMI 2.1: supports 4K at up to 120Hz and 1080p well beyond 240Hz, needed for modern 4K high-refresh TVs and monitors.
- DisplayPort 1.4: comfortably handles 1080p at 360Hz and 1440p at 240Hz+ with compression (DSC) for higher combinations.
- DisplayPort 2.1: built for the newest 4K 240Hz+ and 1080p 500Hz+ monitors, requiring a certified cable to hit full bandwidth.
Always check both your GPU output and monitor input specs — a cable can only carry as much bandwidth as the weaker end of the connection supports, and an unrated or overly long cable can silently fall back to a lower refresh rate.
# Benchmark Reference Table
| Refresh rate | Frame interval | Ideal competitive games | Cable requirement |
|---|---|---|---|
| 60Hz | 16.67ms | Casual / non-competitive play | Any HDMI/DisplayPort |
| 120Hz | 8.33ms | Console competitive, general gaming | HDMI 2.0+/DP 1.2+ |
| 144Hz | 6.94ms | Entry-level competitive FPS | HDMI 2.0+/DP 1.2+ |
| 165Hz | 6.06ms | Competitive FPS, general esports | DP 1.2+ |
| 240Hz | 4.16ms | Valorant, CS2, Apex Legends | DP 1.4/HDMI 2.1 |
| 360Hz | 2.77ms | High-level competitive FPS/esports | DP 1.4+ |
| 540Hz | 1.85ms | Elite/pro-level esports setups | DP 2.1 |
# Frequently Asked Questions
This is almost always an operating system or cable setting rather than a monitor fault. Check your display settings menu to confirm the refresh rate is actually set to its maximum, and make sure you're using a cable rated for that refresh rate at your resolution, since an HDMI or DisplayPort cable that's too old or too long can silently fall back to a lower rate.
Variable refresh rate technologies like G-Sync and FreeSync let your monitor's refresh rate fluctuate to match your PC's rendered frame rate rather than staying fixed, which can make a single measured number less meaningful. For a stable baseline reading, consider disabling VRR temporarily or ensure your browser is rendering consistently at or above your monitor's rate during the test.
Yes. If hardware acceleration is disabled in your browser's settings, frame rendering is handled by the CPU instead of the GPU, which can cap measured performance well below your monitor's actual refresh rate. Make sure hardware acceleration is enabled in your browser settings for an accurate reading.
Browsers typically sync rendering to the display that currently contains the browser window, so moving the window to a different monitor with a different native refresh rate will change the measured result. If you have mismatched monitors, run this test with the browser window fully on the specific display you want to measure.