Monitor test
Check a display the way a panel inspection bench would: pixel by pixel, frame by frame, grey step by grey step. Every test runs in your browser, full-screen, with nothing to install.
Quick check: click or press → to step through black, white, red, green, blue and two greys. Esc exits.
Pixels
Motion & timing
- Refresh rate testEstimates your real Hz from frame timing, with a dropped-frame graph.
- FPS comparisonSide-by-side lanes at 15, 30, 60 fps and your full refresh rate.
- UFO motion blur testMoving targets that show persistence blur, with a strobe option.
- Ghosting testA pursuit pattern for judging response time and overdrive overshoot.
- Input lag testClick-to-flash latency of your whole chain, averaged over many tries.
Panel & backlight
- Backlight bleed testA true black screen to spot edge bleed, IPS glow and clouding.
- Uniformity testGrey fields for dirty-screen effect, vignetting and tint shifts.
- Viewing angle testPatterns that change visibly when you look off-axis.
- Sharpness & text clarity1-pixel lines, small text and a subpixel layout check.
Tone & colour
- Color banding testSmooth gradients that expose 6-bit panels and posterisation.
- Gamma testCheckerboard chart to read your gamma against the 2.2 target.
- Black & white level testNear-black and near-white steps for crushed shadows and clipped highlights.
- Monitor color testColour bars, saturation ramps and a calibration checklist.
A 15-minute check for a new monitor
Most retailers give you a short window to return a faulty panel, so test in this order. Let the monitor warm up for 15–30 minutes first; backlight and colour drift while it is cold.
- Reset to defaults, then set the resolution and refresh rate. Use the panel's native resolution and pick the highest refresh rate in your OS display settings (Windows: Settings → Display → Advanced display; macOS: System Settings → Displays). A 144 Hz monitor left at 60 Hz is the single most common "fault" we see described.
- Dead and stuck pixels on black, white and the three primaries. Wipe the screen first, because dust looks exactly like a dead pixel until you move it.
- Backlight bleed in a dim room at about 30% brightness, judged from normal seating distance, not with a phone camera on long exposure.
- Refresh rate: confirm the browser sees roughly the Hz you set.
- Motion: the UFO test for blur and the ghosting test to pick the best overdrive setting.
- Tone: banding, gamma and black level. Crushed shadows often mean an RGB range mismatch, not a bad panel.
- Uniformity on mid-grey, and text clarity at your usual scaling.
What a browser can and can't measure. Pattern tests are exact: the page puts precise pixel values on screen and your eyes do the judging. Timing tests (refresh rate, input lag) are estimates from the browser's frame clock. Colour tests show what your monitor does with the signal after your OS colour profile has been applied, so they are a check, not a calibration. For a true calibration you need a hardware colorimeter.
Questions people ask
Are online monitor tests accurate?
Pattern tests (dead pixels, bleed, uniformity, banding, gamma charts, sharpness) are as accurate as your eyes, because the page simply shows exact pixel values full-screen. Timing tests are estimates: browsers expose frame timing through requestAnimationFrame, which is good enough to tell 60 Hz from 144 Hz but not a lab measurement. Colour appearance also depends on your operating system colour profile.
What should I test first on a new monitor?
Dead pixels and backlight bleed first, because they are the most common reasons to return a panel and many retailers have short return windows. Then check that the refresh rate matches the advertised figure, then motion (UFO and ghosting), then tone (banding, gamma, black level).
Do I need to install anything?
No. Every test runs in the browser. The full-screen tests use the standard Fullscreen API, and nothing about your screen is uploaded.
Do these tests work on phones and TVs?
Yes, pattern tests work on any screen with a modern browser. On phones, turn off auto-brightness and night mode before judging colour or uniformity.