Device test · Display
Dead Pixel Test
Wipe the screen, then start the guided six-color sequence.
In the sequence: tap or press → for the next color, ← to go back, C to mark the color clean, X to mark a defect on it, Esc to leave. Marking a color moves you to the next one you have not judged. Nothing advances on its own.
Or jump straight to one color:
What you found
Your own answers, recorded as you give them. The page cannot see your screen, so every verdict here is self-reported.
| Screen | Shown | Your verdict |
|---|
- Nothing recorded yet. Run the sequence.
Verdict
NOT RUN
—
Run the guided sequence and mark each of the six screens clean or defect. The verdict appears once all six are judged.
Published thresholds: all six screens judged with none marked is PASS. A mark on both white and black, or on 50% gray alone, is CHECK SETTINGS: dirt or damage on the glass, or a dim patch, rather than a pixel. A mark on white or black alone, or on a primary color without white or black, is LIKELY FAULT: a dead, stuck or hot pixel, or a subpixel fault. Fewer than six judged is NOT RUN. Every mark is self-reported; the page cannot see your screen. Full reasoning in the methodology.
Is it a warranty fault for your brand?
Pick a brand line and enter the dots you counted (a dead or stuck verdict fills in one). Limits come from each brand's policy page, dated: see the warranty matrix.
Choose a brand to compare your count with its published limit.
How this test works
An LCD or OLED pixel is made of three subpixels (red, green, and blue), each driven by its own transistor. A solid full-screen color works as a test because each color isolates a different failure. On pure white every subpixel should be lit, so a dead pixel appears as a sharp black dot. On pure black everything should be off, so a stuck subpixel glows as a colored point and a hot pixel as a white one. The pure red, green, and blue screens name the faulty subpixel by the color of the dot they leave behind, and a 50% gray screen catches partial or dim pixels that full brightness masks. The guided sequence shows all six in that order and prints the guidance for the color on screen, because the same defect can be obvious on one screen and completely invisible on the next.
The log tracks which of the six screens you have displayed, which you marked clean, and which you marked as showing a defect, then reads that pattern back: a dot on white and none on black points at a pixel that will not light, a dot on black and none on white points at a subpixel stuck on, and a dot on both usually means dirt or damage on the glass, since a real pixel fault disappears on at least one of those two screens. Each reading is worded as "consistent with", because your answers are the page's only input. The log also does not record where on the screen you saw a dot, so to the log, two separate defects and one confusing defect look identical. For a warranty claim, write down where each dot sits and read the guide to ISO 9241-307 and dead pixel warranty rules.
The stuck pixel fixer flashes colors over an area you position, at the rate and for the time you choose. When it stops, it reports the area, the rate you set, the number of color changes it drew, the time it ran, and the average rate that works out to. That average is lower than the setting if your browser throttled the tab, and hiding the tab stops the flashing. Before you judge the result, clean the screen and look from straight on.
What each color reveals
The guided sequence reads its prompts from this table: the prompt on each full-screen color is that color's row.
| Screen | What it isolates | Dead pixel (always black) | Stuck pixel (wrong color) | Hot pixel (always white) |
|---|---|---|---|---|
| White | Every subpixel at full brightness | A sharp black or dark dot. This is the screen for dead pixels. | Hidden if the subpixel is stuck on. A subpixel stuck off shows as a colored dot: a dead red subpixel leaves cyan. | Hidden, because a hot pixel is white on a white field. |
| Black | Every subpixel off | Hidden, because a dead pixel is black on a black field. | A bright red, green, or blue point. This is the screen for stuck pixels. | A bright white point, clearest here. |
| Red | Red subpixels only | A black dot. | Yellow means green is stuck on, magenta means blue is; a black dot here with none on white means red is stuck off. | A white dot. |
| Green | Green subpixels only | A black dot. | Yellow means red is stuck on, cyan means blue is; a black dot here alone means green is stuck off. | A white dot. |
| Blue | Blue subpixels only | A black dot. | Magenta means red is stuck on, cyan means green is; a black dot here alone means blue is stuck off. | A white dot. |
| Gray 50% | Every subpixel at half drive | A black dot. | A dot brighter or off-hue against the field. | A white dot. Dim, partly driven pixels and cloudy patches (mura) also show here and nowhere else. |