How the test works

The big number is the refresh rate your browser is drawing at right now. It’s timed over about a second and checked again every few seconds, so it follows the window to another monitor.

When you start, a short “Get ready” list shows the rate again – on a computer, with how to raise it if it’s under 100 Hz – and asks you to close heavy apps and tabs and plug in a laptop, because battery saving can lower the rate.

Then four rows of stripes slide past at 250, 500, 1000 and 2000 pixels per second – Slow, Medium, Fast and Very fast. Follow the moving block with your eyes and click the fastest row where you can still see the separate stripes, or choose “None look sharp”. Meanwhile the page measures how evenly frames arrive. The stripes never flash, but you can skip this step if moving patterns bother you.

The result rates motion clarity from “Blurry” to “Excellent” and shows the measured Hz and whether frames were steady.

What refresh rate means

Refresh rate is how many new pictures per second your screen shows, measured in hertz (Hz). At 60 Hz each picture stays on screen for 16.7 ms; at 144 Hz, for 6.9 ms. A higher rate makes motion smoother and sharper: most screens hold each picture until the next one arrives, so a moving object smears as your eyes follow it. The shorter each picture stays, the less it smears.

A browser can’t read the maximum your monitor supports. It measures the rate it is actually drawing at, which can be lower – for example when the display is set to 60 Hz, when the tab is in the background, or when a laptop is on battery. A dropped frame is a moment when the browser misses its turn to draw, so motion briefly stutters.

If the number is lower than expected

• Under 100 Hz: if your monitor supports more, choose it. Windows: Settings → System → Display → Advanced display → Choose a refresh rate. Mac: System Settings → Displays → Refresh rate. Many laptop screens are 60 Hz – that’s normal.
• Cable: use DisplayPort or HDMI 2.1 – older cables and ports can limit the rate. If your desktop PC has a separate graphics card, plug the monitor into it, not into the motherboard.
• Dropped frames: turn on hardware acceleration in the browser (Chrome: Settings → System → Use graphics acceleration when available; Edge: the same switch under Settings → System and performance), close heavy tabs and apps, and plug in a laptop.
• Blurry motion at 120 Hz or more: on an LCD, turn on overdrive, a setting that makes pixels change faster (often “Response time: Fast”). Also check that no eco mode limits the rate.

Buying a used monitor? Also check for dead pixels and, on OLED, burn-in.

More single tests

• HDR brightnessHow bright highlights get, and how much big bright areas dim.
• Black levelTrue black and the darkest shadow detail.
• GradientsStripes in smooth colour ramps – 8-bit or 10-bit.
• ColoursStandard sRGB, Display-P3 or beyond.
• Dead pixelsDark or stuck dots on full-screen colours.
• Burn-inFaint shapes left by static images on OLED.
• UniformityPatches, darker edges and backlight bleed.