How to Check for Dead Pixels: Telling Stuck and Dead Pixels Apart

What is a dead pixel? Stuck pixels vs dead pixels

LCD and OLED screens are made of a dense grid of pixels, each built from three tiny lights (subpixels): red, green, and blue. A pixel defect means one of those pixels or subpixels no longer lights up the way it should. Defects fall into two main types, depending on how they look.

Stuck pixels are the most noticeable. A single red or green dot glowing against a black background catches your eye in dark movie scenes and in dark mode. Dead pixels, on the other hand, are often invisible unless you stare at a white background, and many people never notice them in everyday use.

Subpixel faults are easy to miss because they look almost white on a white screen. For example, a pixel whose red subpixel never lights looks only faintly cyan on white, but it shows up clearly as a black dot on a solid red screen.

How to check with full-screen solid colors

The most reliable way to find pixel defects is to fill the entire screen with a single color. Any icons or text left on screen can hide the dots beneath them. You can follow the steps below directly on the Dead pixels & burn-in screen of the Screen Checker.

1. 1

   Wipe the screen clean

   Fingerprints and dust look like dead pixels on a white screen and, by reflecting light, like stuck pixels on a black one. Wipe the screen first with a soft cloth such as a lens cloth.

2. 2

   Turn the brightness all the way up

   If auto-brightness or power saving has dimmed the screen, dead pixels blend into the background. Set brightness to maximum manually for the duration of the check.

3. 3

   Go full screen and start with black

   Switch through black, white, red, green, and blue in that order, scanning from the top left to the bottom right and all the way to the edges. Spend about 20 to 30 seconds on each color.

4. 4

   Photograph anything suspicious

   If you find a dot, take a close-up photo with your phone while that color is still on screen. It serves as evidence when you contact the retailer and saves you from describing its position in words.

Telling dead pixels apart from dust, scratches, and bubbles

A “black dot” very often turns out to be dust on the surface or an air bubble under a screen protector. These three checks settle most cases.

• Does it change with the color? A pixel defect stands out only on certain colors. Dust and scratches look about the same on every color.
• Does it shift when you change your viewing angle? Surface dust and protector bubbles appear to move relative to the pixels when you move your head side to side. A pixel defect is the pixel itself, so it stays in exactly the same place.
• Is it exactly one pixel in size? Under a magnifier or your camera’s zoom, a pixel defect is exactly one square pixel (or one subpixel stripe). If it is round, blurry, or bigger than a pixel, suspect dust or debris inside the panel.

A faint copy of a previous image lingering on screen is not a dead pixel but image retention or burn-in. See how to tell image retention from burn-in for how to distinguish them.

What to do if you find one, and how warranties work

Because panels have so many pixels, many manufacturers state in their manuals that a small number of defects is within specification, often phrased as “99.99% or more effective pixels.” A 4K screen (3840 × 2160) has roughly 24.88 million subpixels, and 0.01% of that is about 2,488. That is why a single defective pixel may not qualify for an exchange or return.

• Check the retailer’s return or exchange window first: shortly after purchase, the store may exchange the unit at its own discretion. The period varies by store, so check your receipt or the terms on your order.
• Check for a zero-bright-dot or pixel policy: depending on the model and the retailer, some monitors come with a guarantee to replace the unit for even one stuck pixel, sometimes for a limited period or as a paid option.
• Have the details ready: model name, purchase date, the dot’s type and color (stuck or dead, and which color), its position (roughly how many centimeters or inches from the top left), and your photos. This speeds things up considerably.

Tips for monitors vs. phones

Monitors are large, so it is easy to miss dots near the edges. Mentally divide the screen into four quadrants and check one at a time to avoid gaps. For other checks worth doing when you buy a new monitor, such as uneven color and backlight bleed, see the new monitor defect checklist.

Phone screens are very fine, so stuck pixels look tiny. Holding the phone about 20 cm (8 inches) from your face makes them easier to spot. In environments that cannot go full screen, such as Safari on iPhone, the area under the address bar may stay hidden, so rotate the phone and check in both portrait and landscape. For a full-screen inspection when buying a used phone, see the used phone screen check.

FAQ

Which colors should I use to check for dead pixels?

Stuck (always-on) pixels are easiest to see on black, and dead (always-off) pixels on white. Subpixel faults show up on solid red, green, and blue. The standard approach is to display black, white, red, green, and blue full screen, one after another.

Will they replace my screen for just one dead pixel?

Many manufacturers treat a small number of pixel defects as within specification, so one defect alone may not qualify. Check whether you are still within the retailer’s return window and whether the manufacturer offers a zero-bright-dot or pixel guarantee, then contact them with photos.

How can I tell a dead pixel from dust?

If it looks the same on every color and seems to shift when you move your head, it is surface dust or a bubble under the screen protector. If it stands out only on certain colors and stays on the same pixel from any angle, it is a pixel defect.

Can new dead pixels appear later?

Yes, new ones can appear over time, and drops or pressure on the screen can trigger them. If you are concerned, repeat the same check occasionally so that you catch any defects while the device is still under warranty.