Dead pixel test

Run it full screen

Search each color from edge to edge, then count the dots and note where each one sits. The colors follow Dell's method: black, white, red, green and blue. We added gray, where both lit and dark dots show. On a touch screen, tap the right two thirds to go forward and the left third to go back.

Turn on the magnifier to hold one spot in a ring while the colors change. It also shows which parts of a healthy pixel light up on each color.

Dead, stuck or hot pixel

Brands name these faults differently: Dell calls a white dot stuck, and the withdrawn ISO 13406-2 standard called it hot.

• Dead pixel A black dot on white, gray and every color, invisible on black. All three subpixels are off.
• Stuck pixel A red, green or blue dot that shows on black. One subpixel is stuck on.
• Two stuck subpixels A yellow, cyan or magenta dot on black, JScreenFix explains: two of the three are stuck on.
• Hot pixel A white dot on black: all three subpixels are stuck on.
• Dark subpixel A small dark spot on white, often tinted rather than black: one subpixel is stuck off.
• Dust Wipes off. Material caught inside the glass has an irregular outline and stands out most against white.

A dot that moves or changes color is not a pixel fault. Neither is light leaking at the rim of a black screen, which is backlight bleed, or a faint taskbar outline on an OLED, which is burn-in.

How many dead pixels a maker accepts

Panel sellers often grade screens by the pixel fault classes of ISO 9241-307. It replaced ISO 13406-2, and ISO confirmed it as current in 2024. The limits count per million pixels, so they grow with the screen resolution. A 1920 x 1080 panel has 2,073,600 pixels, so Class II allows it about 4 lit and 4 dark ones.

The figures come from FORTEC (2025) and ISIC (a 2015 document, posted 2025), display sellers that cite the paywalled standard. A lit subpixel counts as two dark ones, so each subpixel column assumes none of the other kind.

Warranties follow the maker's own policy. Dell replaces a Premium Panel Exchange monitor, such as an UltraSharp or a G series, for a single bright pixel, and it allows up to 5 dark subpixels. Its standard lines allow up to 5 bright pixels and 5 to 15 faults in all, depending on the series. The smaller your pixels, the harder one fault is to spot: the PPI calculator gives their size.

Fixing a dead or stuck pixel

A dead pixel can't be fixed: Dell says nothing brings one back, and the remedy is a new panel. A stuck pixel, Dell adds, stays stuck until the monitor is replaced.

Pixel fixers flash colors over the spot, but no controlled study shows that they work. There are vendor claims, such as JScreenFix's, and single reports. A PCWorld editor's stuck pixels cleared after 10 minutes of a browser tool, on one monitor. Dell advises against fixers and against pressing on the screen, which can crack it, and says either may void the warranty. FORTEC, a display seller, describes gently rubbing the spot, which Dell's advice rules out.

What works is the warranty: count the faults with this test, check them against the maker's policy above and claim before the warranty runs out.

How the dead pixel test works

We fill a canvas the size of your screen, in device pixels, with one color at a time. A solid color has no detail, so scaling and zoom can't hide a dot. By the conversion rules in the W3C's CSS Color 4, sRGB red converted for a wide-gamut panel can light some green and blue too. So on a screen that reports a Display P3 gamut, we draw red, green and blue with P3's own primaries.

You judge by eye; we measure nothing. Where your browser allows it, your screen stays awake during the test, and nothing is sent anywhere.