DeadPixelTest.pro

4K Dead Pixel Test

Click Full Screen and scan each solid color at close range. 4K pixels are tiny — you need to be within 40–50 cm to reliably spot a single defect.

Press F11 for best results on desktop

Why 4K Makes Dead Pixels Harder to Find

A 4K UHD panel (3840 × 2160) contains over 8.3 million pixels — four times the pixel count of 1080p. At common display sizes, pixel density reaches 109–163 PPI, making individual pixels smaller than anything the naked eye resolves at a normal viewing distance. A single dead pixel on a 32-inch 4K monitor is a 0.2 mm dot; on a 27-inch panel it shrinks to 0.16 mm.

The practical consequence: test at close range first. Sit or stand 30–50 cm from the screen and scan each color systematically in overlapping horizontal strips — left to right, top to bottom. A single pass at arm's length is not enough on a 4K panel. Once you identify a defect, step back to your normal viewing distance to assess whether it actually affects your use.

Screen sizePPI at 4KPixel sizeRecommended test distance
24 inch184 PPI0.14 mm25–35 cm
27 inch163 PPI0.16 mm30–40 cm
32 inch138 PPI0.18 mm35–50 cm
43 inch102 PPI0.25 mm50–70 cm
55–65 inch TV80–67 PPI0.32–0.38 mm80–120 cm

4K Dead Pixel Policies

ISO 13406-2 Class II permits approximately 2 bright and 2 dark defects per million pixels. On an 8.3 MP 4K panel that works out to roughly 16 technically allowed defects — though most brands set a practical replacement threshold of 3–5 visible defects. Dell's Premium Panel Guarantee (XPS, Alienware, Precision) remains the most generous, replacing displays for even a single bright stuck pixel. For a full breakdown by brand see our dead pixel warranty guide.

If you find a stuck pixel rather than a dead one, try the stuck pixel fix tool before contacting support — stuck pixels on LCD 4K monitors respond to rapid color cycling more often than OLED panels.

4K Dead Pixel FAQ

Are dead pixels harder to see on a 4K monitor?+
Yes. At 27 inches, a 4K panel packs 163 pixels per inch — each pixel is 0.156 mm wide. At a 60 cm viewing distance a single dead pixel subtends about 0.015 degrees of arc, close to the limit of naked-eye resolution. Move to within 40 cm to spot borderline defects.
How many dead pixels will manufacturers replace a 4K monitor for?+
Most 4K consumer monitors follow ISO 13406-2 Class II, which permits roughly 16 pixel defects on an 8.3-megapixel panel. Dell XPS and Precision lines offer a Premium Panel Guarantee with zero tolerance for bright pixels. Other brands typically require 3–5 defects minimum.
Does this test actually run at 4K?+
Yes — the solid color fills your entire browser canvas at native resolution. No upscaling is applied. The test is pure solid color, so every pixel either renders the correct color or reveals itself as defective.
Can I use this test on a 4K TV?+
Yes. Open the page in your TV browser or cast from a laptop via HDMI. Go full screen and test from 1 metre to find defects, then from normal viewing distance to judge visibility. See the TV dead pixel guide for brand-specific warranty information.

Found a stuck pixel?

Run the fix tool for 10–20 minutes before contacting your manufacturer.

Try Pixel FixerWarranty Guide