What Is a Dead Pixel Test?
A dead pixel test shows a series of solid full-screen colors - usually black, white, red, green, and blue - so you can visually inspect your monitor for pixels that don't display correctly. This works on any screen: monitors, laptops, and even phone or tablet browsers.
How to Use the Dead Pixel Test
- Clean your screen gently, set a comfortable brightness, and choose one of the 11 solid inspection colors. Start with white, black, red, green and blue; light and dark gray help you check subtle variations.
- Click Start Fullscreen Inspection to fill the display with the selected color. If your browser blocks fullscreen, the tool uses a page-covering fallback, but browser bars may remain visible.
- Check the center, edges and corners carefully. Tap or click the empty test area, press Right Arrow or Space for the next color, and Left Arrow for the previous one. Press H to toggle on-screen controls, or Esc to exit fullscreen.
- If you prefer, choose an automatic color cycle of 5, 10, 15 or 20 seconds. It works with solid colors only, pauses while the tab is hidden, and avoids rapidly flashing sequences. Manually step through colors if you are sensitive to changing screens.
- Use the optional grayscale gradient, checkerboard or stripe patterns for additional visual-uniformity checks; these are not measurements of individual hardware pixels. Return to solid colors for dead/stuck pixel inspection.
- When you notice a suspicious spot, press M to make a manual observation mark while inspecting. After exiting fullscreen, use Record a visual finding to describe the spot, its approximate screen area and an optional note.
- Compare the spot against several solid colors. Review your manually recorded entries and select Export CSV to save them. Reset Session clears the timer, viewed colors and notes. No automatic defect count or hardware diagnosis is generated.
How It Works
This tool uses the browser's Fullscreen API to display a single solid color across your entire screen with no menus, icons, or distractions. Dead and stuck pixels are easiest to spot against pure, uniform color fields - which is why real photos or videos aren't useful for this kind of test.
Understanding Your Results
| What you see | Likely issue |
|---|---|
| Black dot on light backgrounds | Dead pixel (no power reaching it) |
| Colored dot that stays the same across all colors | Stuck pixel (locked to one color) |
| Bright white/colored dot on black | Hot pixel (always fully on) |
| No visible dots on any color | Screen is likely healthy |
A single dead or stuck pixel usually doesn't affect daily use, but multiple pixels clustered together can indicate a panel that's degrading.
Benefits
- Free way to inspect a screen before buying a used monitor or laptop.
- Useful for warranty claims - many manufacturers require proof of dead pixels.
- Works on any device with a browser, no software needed.
Common Mistakes to Avoid
- Testing in a bright room - glare can hide faint stuck pixels; dim the lights.
- Only checking one color - some faults only show up on specific colors.
- Confusing dust or a smudge for a dead pixel - wipe the screen gently first.
Frequently Asked Questions
Can a dead pixel be fixed?
True dead pixels usually can't be fixed since the transistor itself has failed. Stuck pixels sometimes respond to gentle massage techniques or pixel-refreshing software, but success isn't guaranteed.
How many dead pixels are considered acceptable?
This varies by manufacturer. Many allow a small number (often 1–5) within their warranty policy before considering a replacement, so check your specific manufacturer's dead pixel policy.
Does this test work on phone screens?
Yes, open this page in your phone's browser and use the fullscreen swatches the same way you would on a desktop monitor.
What's the difference between a dead and a stuck pixel?
A dead pixel shows no light at all, appearing black on every color. A stuck pixel is locked to a single color like red or green regardless of what's supposed to display.
Dead Pixels vs. Stuck Pixels - Not the Same
A dead pixel has lost power completely and stays permanently black, usually from a transistor failure or physical damage. A stuck pixel still gets power but freezes on one color, often because the liquid crystal isn't rotating properly. This matters because stuck pixels can sometimes be fixed by rapidly cycling colors over that spot, while dead pixels are permanent and need panel replacement. Manufacturers also apply different dead pixel policies for warranties, so knowing exactly how many and which type you have matters when filing a claim.
Conclusion
Running through each color for even 10–15 seconds can reveal panel issues you'd otherwise miss during normal use. If you're checking a monitor before purchase, also try the Refresh Rate Test and Monitor Color Test for a full picture of display health.