Dead Pixel Test by Resolution
Pick your screen resolution for a tailored dead pixel test. Higher-resolution panels pack pixels tighter, changing how close you need to be to spot a defect and how many defects manufacturers permit.
Choose your resolution
4K / UHD Dead Pixel Test
4K- Resolution
- 3840 × 2160
- Density
- 109–163 PPI (27–43 inch)
- Pixel size
- 0.16–0.23 mm
Lean in to 30–50 cm — 4K pixels are near the limit of naked-eye resolution at normal viewing distance.
Run test →1440p / QHD Dead Pixel Test
2K- Resolution
- 2560 × 1440
- Density
- 92–122 PPI (24–32 inch)
- Pixel size
- 0.21–0.28 mm
The most popular gaming monitor resolution. Test from 50–65 cm — defects are visible but not obvious on a quick scan.
Run test →1080p / Full HD Dead Pixel Test
FHD- Resolution
- 1920 × 1080
- Density
- 68–105 PPI (21–32 inch)
- Pixel size
- 0.24–0.37 mm
Dead pixels are clearly visible at arm's length on a 1080p screen — a single defect is hard to miss on a white background.
Run test →Ultrawide Dead Pixel Test
21:9- Resolution
- 3440 × 1440 · 5120 × 1440 · 2560 × 1080
- Density
- 21:9 and 32:9 aspect ratios
- Pixel size
- Up to 7.37 M total pixels
Scan in three vertical zones — ultrawide screens are too wide to check in a single visual sweep.
Run test →Resolution comparison
All PPI and pixel-size figures are for a 27-inch display unless noted.
| Resolution | Pixel count | Total pixels | PPI | Pixel size | Test distance |
|---|---|---|---|---|---|
| 4K / UHD | 3840 × 2160 | 8.29 M | 163 PPI (27") | 0.16 mm | 30–50 cm |
| 1440p / QHD | 2560 × 1440 | 3.69 M | 108 PPI (27") | 0.23 mm | 50–65 cm |
| 1080p / FHD | 1920 × 1080 | 2.07 M | 81 PPI (27") | 0.31 mm | 50–70 cm |
| Ultrawide 21:9 | 3440 × 1440 | 4.95 M | 110 PPI (34") | 0.23 mm | Zone scan (3 passes) |
How resolution affects dead pixel visibility
Resolution determines pixel density — how many pixels fit into each inch of your screen. The higher the density, the smaller each individual pixel. A dead pixel on a 4K monitor is a 0.16 mm black dot; the same defect on a 1080p screen at the same size is 0.31 mm — nearly twice as wide and far more obvious.
This matters for testing: at 4K you need to lean in to 30–40 cm and scan methodically. At 1080p a quick visual sweep from your desk chair is enough. The tools are the same — solid color backgrounds across seven colors — but the technique and how carefully you need to look differ by resolution.
Resolution also affects warranty thresholds. ISO 13406-2 Class II permits approximately 2 bright defects per million pixels. On a 4K panel (8.3 MP) that allows ~16 technically permitted defects. On a 1080p panel (2.07 MP) it is ~4. In practice most manufacturers and retailers will address a single bright pixel near the center within the first 30 days regardless of the threshold.
Frequently asked questions
Does screen resolution affect dead pixel visibility?+
Yes. Higher resolution panels pack more pixels into the same physical area, making each pixel smaller and harder to spot. A dead pixel on a 27-inch 4K monitor is 0.16 mm — near the limit of naked-eye resolution at normal distance. The same defect on a 27-inch 1080p screen is 0.31 mm and clearly visible without leaning in.
Which resolution should I test at?+
Test at your display's native resolution. The tool fills your entire browser canvas automatically. Choose the page that matches your panel for resolution-specific viewing distance advice and warranty information.
Do dead pixels occur more at higher resolutions?+
Not per pixel — manufacturing defect rates are similar. But a higher-resolution panel has more total pixels, so the statistical chance of at least one defect is slightly higher on a 4K monitor than on a 1080p one.
What is the best color to use for dead pixel testing?+
Black reveals stuck (bright) pixels most clearly. White reveals dark dead pixels best. Testing on all seven colors — black, white, red, green, blue, yellow, gray — catches every type of defect, because each stuck pixel hides on its matching color background.
Not sure which resolution you have?
Use the full 7-color test — it works at any resolution and catches every type of pixel defect.