Dead Pixel Test
A dead pixel test fills your screen with solid colors so isolated pixels that don’t match the field become obvious. Dead pixels stay black on every color; stuck pixels stay lit on one color and sometimes recover.
The screen fills with each solid color. Use ← → or click/tap to change color, and Escape to exit. Inspect for pixels that stay a different color (dead) or stuck on one color. No result is automatically decided — you confirm what you see.
How this test works
Display tests render precise patterns or measure timing directly in your browser. Color and pixel tests fill the screen with exact CSS colors so you can inspect the panel; gradient and sharpness tests draw fine structures that reveal banding or scaling.
Timing tests such as refresh rate and FPS sample requestAnimationFrame, which the browser calls once per display refresh. We discard warm-up frames, then report the median interval with a confidence level based on how consistent the samples are.
Full-screen tests use the Fullscreen API and hide all interface so nothing distracts from the panel. You can always exit with Escape, and reduced-motion preferences are respected for animated patterns.
How to use it
- Set your browser zoom to 100% so pixel-level patterns aren’t scaled.
- Start the test; for full-screen tests, use the on-screen or keyboard controls to change patterns.
- Inspect the whole screen carefully from a normal viewing distance.
- For timing tests, keep the tab in the foreground and let the sample finish.
- Press Escape or the exit button to leave full screen when you are done.
What it detects
- Dead or stuck pixels, and non-uniformity visible as color or brightness patches
- Banding in gradients and loss of detail in near-black or near-white patches
- A browser-observed estimate of refresh rate and rendering frame rate
- Your reported screen resolution, pixel ratio and color depth
What it can’t detect
- Laboratory-grade color accuracy, contrast ratio, or millisecond response time
- The panel’s true bit depth when the OS or browser reports a scaled value
- Whether variable refresh rate (VRR) or scaling is altering the result
Troubleshooting
| Symptom | What to do |
|---|---|
| Refresh-rate reading fluctuates | Bring the tab to the foreground, disable battery saver, and remember VRR displays vary by design. |
| Patterns look blurry | Set browser zoom to 100% and your OS display scaling to a native value. |
| Full screen won’t start | Some browsers require a direct click and disallow full screen in embedded contexts; try again with a direct interaction. |
| Can’t tell dust from a dead pixel | Clean the screen first, then inspect the same spot across several solid colors. |
FAQ
What’s the difference between a dead and stuck pixel?
A dead pixel stays black (no sub-pixels lit); a stuck pixel stays on one color. Stuck pixels sometimes recover; dead pixels usually don’t.
How should I inspect?
View each solid color full-screen from a normal distance and look for dots that don’t match the field.
Is any result decided automatically?
No. You confirm what you see — the test only shows the colors.
Can I fix a stuck pixel?
Sometimes. A rapid color-cycling routine may revive a stuck (not dead) pixel; there’s no guarantee.
Is one bright dot always a defect?
Clean the screen first — dust and smudges are common false alarms — then re-check across several colors.
Related tests
Full-screen primary, secondary and grayscale fields with labels to inspect color reproduction.
Smooth horizontal and vertical gradients to inspect banding, in grayscale and color.
Estimate how many times per second your display updates by sampling animation frames, with confidence and background-tab detection.