This dead pixel test fills your screen with one pure color at a time, so any pixel that does not change with the rest of the screen stands out. As a dead pixel tester it works on monitors, laptop screens, TVs and phones, on Windows, Mac, ChromeOS, Android, iPhone and iPad, and it draws every color at your screen's real resolution, one browser pixel to one screen pixel. When you find a faulty dot, mark it. The page records where it is and what it looked like, so you can copy a report or download a map of the spots for a warranty claim.
How to run the dead pixel test
- Wipe the screen with a dry microfiber cloth first. Dust and smears are the most common thing mistaken for a dead pixel.
- Turn off Night Light on Windows, Night Shift and True Tone on Apple devices, and any blue light or eye comfort filter on a phone. They tint white, which hides colored faults.
- Dim the room lights and set the screen to the brightness you normally use.
- Press Start full screen test. The test opens on black. Look across the screen in sections from about 30 cm away: top left, top right, bottom left, bottom right, then the middle.
- Press Space, click or tap for the next color: white, red, green, blue, cyan, magenta, yellow and grey. ← goes back.
- When you see a faulty dot, press M and click right on it, or hold a finger on it on a touch screen. Press L for a loupe with the exact pixel coordinates under the crosshair.
- Press Esc to leave. The spot map under the test lists every spot, and Copy report gives you text you can paste into a support ticket.
Testing a TV or a phone that has no keyboard? Choose a size under Image size and press Save image for each color. Copy the images to a USB stick for the TV, or open them in your phone's photo app, which shows them edge to edge.
What the results mean
| Color on screen | What a fault looks like | What it means |
|---|---|---|
| Black | A white, red, green or blue dot | Stuck or hot pixel: one or more of its parts is stuck on |
| White | A black dot | Dead pixel, if it is also black on every other color |
| White | A cyan, magenta or yellow dot | One part has failed: cyan means red is out, magenta means green is out, yellow means blue is out |
| Red, green or blue | A black dot that is not black on white | That one part, called a sub-pixel, is dead |
| Grey | A dot slightly darker, lighter or tinted | A weak or partly stuck pixel, often missed on the other colors |
The readouts under the test show the size your browser draws at, which should match your screen's native resolution, and how many spots you have marked, split into lit spots found on dark colors and dark spots found on light ones. Makers count those two kinds differently, so the split matters for a claim.
To study one color for longer, open it on its own page, such as the green screen or the yellow screen test, where a stuck blue sub-pixel shows as a white dot.
Dead, stuck and hot pixels, and dust
Each pixel on an LCD is three sub-pixels, one red, one green and one blue, each behind its own tiny transistor. OLED screens light each sub-pixel directly, and some arrange them in other patterns, but the faults look the same.
- Dead pixel. The transistor or its connection has failed, so the pixel stays dark on every color. On IPS, VA and OLED screens that means black. Older TN panels pass light when a transistor fails, so a dead pixel on a TN screen can stay bright white.
- Stuck pixel. One or two sub-pixels stay on or off. It shows as a single red, green or blue dot on black, or as a tinted dot on white. Stuck pixels are the ones a stuck pixel fixer can sometimes free.
- Hot pixel. All three sub-pixels stay on, so the dot is white on black. The term also comes up with cameras: if a bright dot shows in your photos or video calls but not in this test, the camera sensor has the fault, and a camera test will show it.
- Dust or a smear. Dust on the surface moves or vanishes when you wipe the screen. Dust trapped inside the panel layers looks soft edged, larger than a pixel and grey on white, and it does not change color with the test. Zoom in with your phone camera: a dead pixel is a sharp rectangle that lines up with its neighbors.
Glowing edges on a black screen are not pixel faults. That is backlight bleed or IPS glow, which the backlight bleed test covers.
Checking a phone, tablet or TV
Phones and tablets. Open this page in the phone's browser, turn the phone sideways and press Start. Android browsers go full screen. If your browser cannot (Safari on iPhone usually cannot), the test fills the window instead, so scroll the toolbars away or use saved images in the photo app. Hold a finger on a faulty spot to mark it. Phone OLED screens rarely get stuck pixels, so a lasting ghost image is more likely to be burn-in, which the oled burn in test shows better.
TVs. Open the page in the TV's own web browser, or connect a laptop over HDMI and run the test on the TV. Set the TV's picture size to Just Scan, Fit to Screen or Full Pixel first. Otherwise the TV zooms in slightly and hides the outer rows of pixels. The tv test pattern page has an edge check that confirms every pixel is on screen.
Warranty: how many dead pixels are allowed
Most pixel policies grew out of the old ISO 13406-2 standard, whose Class II allowed up to 2 always lit pixels, 2 always dark pixels and 5 faulty sub-pixels per million pixels. Makers now publish their own limits, and they differ by brand, model and country:
| Maker | What the published policy says |
|---|---|
| Dell | Monitors in Premium Panel Exchange, which covers UltraSharp, Alienware and most P and G series, are replaced for a single bright pixel during the warranty. Up to 5 dark sub-pixels are allowed. Lower lines allow up to 5 bright. |
| Acer | Most monitors allow up to 2 bright and 5 dark sub-pixels, 5 in total. The professional BM series allows no bright ones. |
| ASUS | Varies by region. ASUS Australia covers any bright or dark dot for 36 months on monitors bought after February 2022. Elsewhere, selected models have a Zero Bright Dot warranty that excludes dark dots. |
| LG | A table of allowed bright and dark sub-pixels by resolution. Below the limit, LG does not count them as a defect. |
| Samsung | Assessed under your country's warranty. Its published guideline for Thailand, for example, counts one bright dot on a Full HD, QHD or UHD monitor as a fault, while dark dots need several. |
Read the full rules on the Dell pixel guidelines, Acer pixel policy, ASUS pixel policy and LG pixel policy pages. Bright faults count more than dark ones almost everywhere, because they are easier to see. A store's return window is often the easiest route of all, since many stores take a new monitor back for any fault.
What to do about a dead or stuck pixel
- For a colored or white dot, run the dead pixel fix tool for 10 to 20 minutes, then test again. It works on some stuck pixels and never on truly dead ones.
- Give a stuck pixel a few days of normal use. Some clear on their own.
- Do not press on the panel with a finger, pen or cloth. Pressure can turn one bad pixel into a cluster, and Dell warns that home fixes may void the warranty.
- Photograph the fault for a claim: show the color it appears on, hold the phone 10 to 20 cm away, tap to focus on the spot, then take a second, wider photo that shows where it sits on the screen. Attach the spot map and report.
- Out of warranty, a single pixel is cosmetic. The guide on how to fix dead pixels covers repair options and what a panel swap costs in time and money.
A dead pixel test on a monitor only checks the pixels. To check the rest of the panel, the full monitor test adds gradients, gamma, uniformity and sharpness patterns.
What a browser dead pixel test cannot do
The page cannot see your screen. It shows clean colors, and your eyes find the faults, which is also how makers check them. The loupe enlarges the pattern the page draws, not the physical panel, so a dead pixel will not appear inside it. Use it to read exact coordinates while you mark a spot. Coordinates count screen pixels from the top left corner when the test runs full screen. Without full screen they count from the corner of the browser window, and the report says so.
Dead pixel test questions
How do I check my monitor for dead pixels?
Clean the screen, press Start full screen test and look at each color from about 30 cm away. Dead pixels show as black dots on white and on every color. Stuck pixels show as red, green, blue or white dots on black. Mark each one with M so you have its exact position.
Can a dead pixel fix itself?
A truly dead pixel does not come back, because its transistor or connection has failed. A stuck pixel is different. It sometimes clears on its own after a few days of use, and sometimes after 10 to 20 minutes of rapid color flashing.
How many dead pixels are acceptable on a new monitor?
It depends on the maker and model. Dell replaces monitors in its Premium Panel Exchange for a single bright pixel. Acer allows up to 2 bright and 5 dark sub-pixels on most monitors. Others set limits per resolution. Within the store's return window you can usually return the monitor for any fault.
Is it safe to run a dead pixel test on an OLED screen?
Yes. Burn-in needs hundreds of hours of the same image. A few minutes of solid colors does no harm to an OLED, LCD or phone screen.
Do dead pixels spread?
Usually not. A single dead pixel stays a single pixel. A line, a cluster that grows, or a dark patch points to a different fault, such as a loose panel connection or pressure damage, and is worth a warranty claim straight away.
Why do I see a dot on black but not on other colors?
That is a stuck pixel. One or more of its red, green or blue parts is stuck on, so it glows on black. On a bright color its glow blends in. Check whether it shows as a single color, which tells you which part is stuck.