Running on your device · 0 bytes uploaded

# Dead pixel test

Five solid colors, full screen — white, black, red, green, blue. Your eyes are the detector: this tool shows colors; it cannot and does not claim to see your screen.
viewport cycle — White shown nowFullscreenAuto-cycleWhite — #ffffffWhiteBlackRedGreenBlue

Dead (black) pixels — dark specks that never light. The classic first check.

- This test cannot see your screen — it shows known colors full-viewport and your eyes are the detector. No camera, no analysis, no claims about what it found.
- Fullscreen covers the whole panel including browser chrome; without it, the cycle still fills the viewport, which catches most of the screen but not all. Esc exits fullscreen at any time (the browser guarantees it); Space and the on-screen buttons step colors.
- Work through the five colors slowly. A dot that stays dark on white is a dead pixel; a dot that keeps its own color on black is stuck. One sub-pixel channel failing shows only on its color and black — that is why there are three primaries, not one.
- Dust on the panel mimics a dead pixel — clean the screen first. Very small dead pixels can hide at low brightness; the test says nothing about warranty terms, which manufacturers set by count and location.
Nothing in yet

Paste, drop, or type to begin. Everything stays on this device.

a five-color cycle and your eyes — no detection, no analysis, no warranty verdicts

## Next door in Device

- [Refresh rate](/device/refresh-rate)
- [Screen & viewport](/browser/screen)
[All device tools](/device)

---

Canonical HTML: https://nutter.tools/device/dead-pixel
Markdown version: https://nutter.tools/device/dead-pixel/index.md
Plain-text version: https://nutter.tools/device/dead-pixel/index.txt
Agent index: https://nutter.tools/llms.txt