Free Dead Pixel Test
Find dead or stuck pixels with fullscreen solid colors, then try an optional stuck pixel flasher with a seizure warning and consent step.
Loading tool…
How to check a screen for dead or stuck pixels
Fill your screen with solid colors to spot dead or stuck pixels, then optionally run a small flasher to try to free a stuck one.
- Clean the screen with a soft, dry cloth so dust is not mistaken for a pixel fault.
- Select Start fullscreen test. Tap, click, press Space or use the arrow keys to move between colors, and press Escape to exit.
- On each color, scan the screen slowly from edge to edge. A dot that stays black on every color is likely dead; one that stays lit in a single color is likely stuck.
- For a stuck pixel, open Stuck pixel flasher, read the photosensitivity warning and tick the consent box.
- Drag the square over the pixel, choose speed and duration, start flashing, look away, and check the pixel again afterwards.
When to run a dead pixel test
The best time is right after buying a monitor, laptop, phone or TV, while the return window is still open. Retailers and manufacturers often have a pixel policy that sets how many faulty pixels qualify for a replacement, and that period is usually short. A two-minute check on solid colors catches most faults before you lose that option.
It is also useful when buying a used screen, when a small dot keeps catching your eye during work, or after a device has been dropped or pressed. Separating a pixel fault from dust, a scratch or a small smudge saves a needless return.
The test shows plain colors that change only when you ask. Nothing flashes unless you open the separate flasher mode and agree to the warning.
Worked example: checking a 1080p monitor
A 1920 by 1080 monitor has 2,073,600 pixels, each made of red, green and blue subpixels, for 6,220,800 subpixels in total. A single fault is tiny, so scan methodically: start fullscreen on white, then step through black, red, green, blue and gray, looking at the screen in sections from about arm's length.
Suppose a dot stays black on white, red, green and blue. It never lights, so it is a dead pixel, and no software can change that. Now suppose another dot glows green on the black screen and looks bright on red, where green should be off. That is a stuck green subpixel.
For the stuck dot, the flasher can run at 10 color changes per second for 10 minutes, which is 6,000 color changes over that small square. If the dot is still green afterwards, repeat once or twice. If nothing changes, the fault is likely permanent and the warranty is the next step.
How the test and flasher work
The color test fills an element with one solid color and uses the browser's fullscreen mode so menus and toolbars disappear. The pointer hides after a moment so it does not look like a defect, and keyboard shortcuts let you move forward and back or jump to a color with the number keys.
The flasher cycles a movable square through red, green, blue, white and black at three, ten or about thirty changes per second. The idea is to rapidly drive the stuck subpixel on and off, which sometimes frees it. The flasher runs in a small area, stops automatically after the time you choose and stops at once when you press Escape or Space or hide the tab.
Common mistakes with pixel tests
Dust is the most common false alarm. A speck on the glass sits slightly above the image, so it shifts when you move your head; a faulty pixel stays fixed in the grid. Clean the screen before deciding.
Another mistake is testing only on white. Dead pixels show best on white and bright colors, while stuck pixels show best on black. Brightness also matters: very low brightness can hide a dim stuck subpixel.
Finally, avoid pressing hard on a screen to massage a pixel. Pressure can damage the panel and may void the warranty. Check the seller's policy first, since a replacement is often the more reliable fix.
Useful tips and limitations
- Use a dim room for the black screen and full brightness for the white one; each reveals different faults.
- Photograph a fault before contacting the seller, since many warranties set a minimum number of defective pixels.
- Use the custom color option to match a background you use daily if a fault only bothers you in one app.
- Run the flasher in short sessions and check the pixel between them instead of leaving it for an hour.
Common questions
What is the difference between dead and stuck pixels in the Dead Pixel Test?
A dead pixel stays dark on every color because it gets no power. A stuck pixel stays lit in one color, such as red, green, blue or white, because a subpixel is stuck on. Stuck pixels are the ones a flasher sometimes helps.
Can the Dead Pixel Test flasher repair any screen fault?
No. Rapid color cycling occasionally frees a stuck subpixel on LCD screens, but it cannot fix a dead pixel, cracked layers, pressure marks or backlight bleed, and it may not work at all.
Is the Dead Pixel Test flasher safe for people with epilepsy?
No. It flashes bright colors rapidly and can trigger seizures in people with photosensitive epilepsy. It only starts after you read a warning and give consent, and it stops when you press Escape or Space, click the background or hide the tab.
Does the Dead Pixel Test work on phones and OLED screens?
Yes. Tap the screen to change colors. OLED pixels can also fail, though the flasher is mainly aimed at stuck LCD subpixels.
Why does the Dead Pixel Test hide the pointer in fullscreen?
A visible cursor can be confused with a defect. Moving the mouse shows it again together with the control hint.
How many dead pixels allow a return after a Dead Pixel Test?
It depends on the seller and manufacturer. Many publish a pixel policy that counts dead and stuck pixels separately, so check that document for your model.
Your input is processed in your browser without a ToolWorld Online account. Copy or download anything you want to keep before leaving the page.