How to Check a Monitor for Dead and Stuck Pixels — and What to Do If You Find One
Check a monitor for dead and stuck pixels with TryYourGear's Monitor Test, tell them apart from dust, document the defect and check your manufacturer's policy.
A pixel that is always dark or always lit is easy to miss on a busy desktop and hard to unsee on a plain background. Checking takes a few minutes. The useful part comes after you spot a dot: is it the panel or something on the surface, what exactly is it, and what do you need before you contact the seller or the manufacturer?
TryYourGear's Monitor Test shows full-screen patterns and you do the inspecting; below is how to do it well and what to do with what you find.
Don't press on the screen or run pixel-fixing tools
Dell warns against trying to fix stuck pixels yourself: pixel-fixing software and pressure on the screen can cause further damage and may void the warranty, and Dell doesn't officially support that software. Fast-flashing patterns can also be a risk for people with photosensitive seizure disorders; that is why accessibility guidelines limit flashing content.
Know what you are looking for
Manufacturers talk about bright and dark pixels and subpixels for what most people call stuck and dead pixels. Dell defines them this way, and Apple explains how dust can pass for one:
| What it is called | What you see | Where it shows best |
|---|---|---|
| Dark pixel (often called a dead pixel) | A black dot: all three subpixels are off. | White or colored backgrounds |
| Bright pixel (often called a stuck pixel) | A bright white dot that is always lit. | Dark backgrounds |
| Bright subpixel | A small red, green or blue dot that stays lit. | Dark backgrounds |
| Dark subpixel | A small dark spot: one color component is off. | White backgrounds |
| Dust or another foreign particle | Can look like a pixel defect but is not one. Usually irregular in shape. Dust on the front of the glass can often be wiped off; material trapped inside needs professional service. | Most noticeable on white |
Definitions from Dell and Apple. Everyday names vary, so when you contact anyone, describe what you see: the color of the dot and the background where it shows.
Prepare the screen
- Clean it first. Switch the monitor off, use a soft microfiber cloth, avoid pressing hard, and don't spray liquid straight onto the screen or use alcohol or ammonia cleaners, as ASUS's cleaning guide explains.
- Set the scene. Dim the room lights, use your usual brightness and turn off night-light or color-filter features so the patterns show plain colors. What you see also depends on your browser's colour management and your system settings.
Run the Monitor Test
Open a screen
Pick one of the eight screens; it opens over the whole window. Click anywhere, or use the arrow keys, to go to the next one. Fullscreen fills the display, and Esc or Exit leaves the test.
Go through white, black, red, green, blue and gray
Give each screen a proper look before moving on. The table below says what each one can reveal.
Scan each screen in sections
Divide the screen into a grid in your head and move your eyes from section to section, up close. Stop on anything that doesn't match the color around it.
Write down what you find
Note the color of the dot, the screens where you saw it and where it sits on the display. You will need this later.
| Screen | What it can reveal | What to look for |
|---|---|---|
| White | Dark pixels, dark subpixels, dust and specks | Black or dark dots against the white. |
| Black | Bright pixels and bright subpixels | White or colored dots that stay lit. |
| Red, Green, Blue | Problems with a single subpixel | Dots that don't match the color of each of the three screens. |
| Gray | Optional for pixel defects; useful for spotting uneven areas | Patches that look lighter or darker than the rest. |
| Gradient and Checkerboard | Other checks: color banding and sharpness | Not pixel-defect patterns; you can skip them for this check. |
This follows the procedure in Dell's guidelines: cycle through red, green, blue, white and black and look for dots that don't match each background.
What the Monitor Test doesn't do
It shows the patterns and you inspect them. It doesn't count defects, tell you what kind they are, judge whether they are acceptable, or say whether a warranty covers them.
Tell a pixel defect from dust or something on the surface
| What you see | What it points to | How to check |
|---|---|---|
| An irregular speck, clearest on white, that changes or disappears when you wipe the screen gently | Dust or debris on the surface, not a pixel defect. | Clean the screen as above and look at the same screen again. |
| A black dot on white and on the colored screens, at the same spot after cleaning, that you can't see on black | Consistent with a dark pixel. | Note its position, then check it on another source (see below). |
| A bright dot on the black screen, at the same spot after cleaning | Consistent with a bright pixel; a red, green or blue one is consistent with a bright subpixel. | Note its color and position. |
| A small dark spot only on white | Consistent with a dark subpixel, but also with dust. | Clean first, then look again. |
| A dot or line that changes when you change the cable, port, resolution or computer | More likely something in the signal path than a pixel defect. | Test on another source or computer. |
Check whether it's the panel or the signal
A defective pixel belongs to the panel, so it stays in the same physical spot whatever the computer sends. To separate the panel from the computer, the cable and the graphics driver:
- Try another source. Run the same screens on another computer, browser or cable. The same dot in the same place points to the panel or the screen surface.
- Use the monitor's own test, if it has one. Dell monitors have an integrated self-test that works without a signal from the computer and is meant to show whether an abnormality comes from the monitor itself. If the defect appears in it, Dell treats it as a monitor problem; if it doesn't, Dell says to troubleshoot the video connection. How to start it depends on the model, so check your monitor's manual (Dell).
Document the defect
- What and where. The color of each dot, the screens where it is visible and roughly where it sits on the display. Dell asks you to count bright and dark pixels or subpixels separately and note their locations.
- A photo, not a screenshot. A screenshot records what the computer sends, not what the panel shows, so it can't capture a panel defect. Photograph the screen up close with a phone camera, on a plain background where the dot is visible.
- Model and serial number. From the monitor's label or its manual. Dell, for example, checks warranty status with the Service Tag.
- Purchase details. Where and when you bought it, and when you first saw the dot.
- What you ruled out. Cleaning, another source and, if your monitor has one, its built-in test.
Before you return it or make a claim
Whether a pixel defect is covered depends on the seller's return terms and on the manufacturer's policy for your exact model, and both differ. TryYourGear can't tell you which applies, and this is not legal advice.
- Read the manufacturer's pixel policy for your model. Policies differ between manufacturers and even between product lines: Dell, for example, applies stricter coverage to some lines than to standard monitors. Examples of published policies: Dell, Apple, HP, Lenovo and LG.
- Check the seller's return window first, especially with a new monitor: a return or exchange can be simpler than a warranty claim. Terms and consumer rights vary by seller and by country.
- Check your warranty status with the manufacturer, usually with the serial number or service tag.
- Don't assume one rule fits every monitor. A policy that accepts a single defect on one product may not on another. Only your model's policy applies.
Summary
- Clean the screen, dim the room and go through the white, black, red, green and blue screens of the Monitor Test, scanning each one in sections.
- A black dot on white is consistent with a dark pixel; a bright dot on black with a bright pixel; a colored dot with a bright subpixel. Dust can look the same, so clean first.
- A pixel defect stays in the same place on every source. Check another computer or cable and the monitor's own test if it has one.
- Document what you see with a photo, the color and location of each dot, the model and serial number, and when you bought it.
- Read the manufacturer's policy for your exact model, check the seller's return window, and never press on the screen or use pixel-fixing tools.