Dead Pixel Test

Dead pixel test: find black, stuck and bright dots on your screen

Every modern display is a grid of millions of tiny pixels, and each pixel is split into three sub-pixels: red, green and blue. When all of them fire correctly, you get a clean, even image. When one fails or jams, you get a dot that stands out — a black speck, or a stubborn colored point that ignores everything around it. A dead pixel test fills your screen with solid colors so those anomalies have nowhere to hide. Our tool runs entirely in the browser: no installation, no upload, just full-screen color fields you can step through to inspect your panel pixel by pixel.

Dead pixel vs stuck pixel: what is the difference?

The two terms get used interchangeably, but they describe opposite failures. A dead pixel receives no power and never lights up. All three of its sub-pixels are off, so it shows as a permanent black dot, most visible against a white or light background. A dead pixel is essentially a broken transistor; nothing you display on screen changes it.

A stuck pixel is the opposite — it still gets power and stays lit, but it is jammed on a single value. Instead of changing color with the rest of the image, it holds red, green, blue, or some bright combination. A stuck pixel appears as a constant colored or bright dot that ignores the surrounding content. Because it is lit rather than dead, it is most obvious against a black or dark field, where everything else goes off and the stuck point keeps glowing.

This distinction matters for one practical reason: stuck pixels can sometimes be revived, while dead pixels almost never can.

How the solid-color test reveals them

The test works by removing all the visual noise. When the whole screen is one flat color, any pixel that disagrees becomes impossible to miss. The trick is to cycle through several backgrounds, because each color hunts a different kind of defect:

• White — the best background for finding dead (black) pixels. A non-lit pixel stands out sharply on a bright field.
• Black — the best background for stuck or bright pixels, since the rest of the panel goes dark and only the jammed point keeps shining.
• Red, green and blue — these isolate individual sub-pixels. A sub-pixel stuck off on a red field, for example, shows up as a small dark gap.

Sit at a normal viewing distance first, then move closer and scan in a grid pattern, top-left to bottom-right. Wipe the screen with a microfiber cloth before you start — a speck of dust or a smudge looks exactly like a dead pixel and causes a lot of false alarms. If a "defect" moves or wipes away, it was never a pixel problem. For a fuller workout of your panel, pair this with our screen color test to check gradients and uniformity too.

What to do once you find one

If it is a stuck pixel, you have a fair chance of fixing it. Two methods are common. The first is rapid color cycling: a tool that flashes the area through colors at high speed, exercising the pixel's transistor in the hope it unjams. The second is the gentle pressure method — place a soft cloth over the spot, apply very light pressure with something blunt like a pencil eraser while a color-cycling tool runs, then release. Be careful: pressing too hard can permanently damage the panel and the pixels around it. If a few careful attempts produce no change, stop — more force will not help and only adds risk.

If it is a dead pixel, these tricks rarely work. With no power reaching the pixel, there is nothing to cycle or coax back to life, and repair usually means a panel replacement. That is where your warranty comes in.

Checking a new monitor under warranty

The single most useful time to run this test is the day a new monitor or laptop arrives. Manufacturer return windows are often short — sometimes as little as 14 days — and a defect caught early is far easier to act on. Run all the solid colors, note anything you find, and photograph it if you can. Many retailers offer a more generous "zero dead pixel" return guarantee than the manufacturer's baseline, so check the shop's policy as well as the brand's.

Manufacturer dead-pixel policies

Most brands follow the ISO 13406-2 standard, which sorts displays into quality classes and defines how many defective pixels are "acceptable" before a panel qualifies for replacement. Class I allows zero defects and is reserved for medical and professional reference monitors. Class II is the common consumer tier, where one or two isolated dead pixels often fall within the published tolerance — meaning a single dead pixel may not, on its own, be grounds for a swap. Policies still vary: Samsung's published terms entitle customers to a replacement for one or more dead pixels within 14 days of purchase, while professional lines such as ASUS ProArt advertise a zero bright-pixel guarantee. Always read the specific policy for your model and class before assuming you are covered.

When you are done here, explore all device tests to check your screen, speakers, microphone and more.

Frequently asked questions