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Dead Pixel Test — Check Your Screen Online

Dead Pixel Test is a free online tool that fills your entire screen with solid colors — red, green, blue, white and black — so you can spot dead pixels (dots that stay black) and stuck pixels (dots locked on one color) on any monitor, laptop, TV or phone, right in your browser without installing anything. It also includes a stuck-pixel fixer that rapidly flashes colors to try to revive a stuck subpixel.

100% in your browser — nothing uploaded or installed

Start the screen test

Click below to go full screen, then step through the colors with the on-screen buttons, your keyboard (← →, Space) or by tapping the sides of the screen on a phone. Press Esc to exit at any time.

How to test your screen for dead pixels

1

Clean the screen

Wipe the display with a soft cloth first — dust and smudges are easily mistaken for stuck pixels. Then turn brightness up to maximum.

2

Go full screen

Click Start full-screen test. The page fills the whole display with one solid color and hides the cursor so nothing distracts your eye.

3

Cycle the colors

Step through red, green, blue, white and black. Inspect the glass closely — a magnifier or your phone camera helps. A defect that hides on one color jumps out on another.

4

Mark & fix

Note where any odd dots sit. If one is locked on a color (stuck), run the built-in fixer over that spot for 10–30 minutes to try to revive it.

Dead pixel vs stuck pixel — how to tell them apart

People use the terms interchangeably, but they are different faults and only one is usually repairable. The full-screen color cycle is designed to expose both:

TypeWhat you seeBest background to spot itFixable?
Stuck pixelA constant bright dot — red, green, blue or white — that never changes. The subpixel is powered but frozen.Black, and the opposite solid colorsOften yes — try the fixer
Dead pixelA tiny black dot that stays dark on every color. The pixel gets no power at all.White and bright colorsRarely — usually permanent
Hot pixelA pixel always lit bright white, most obvious against black.BlackSometimes — try the fixer
Dust / smudgeA spot that moves or wipes away, or sits on top of the glass rather than within it.WhiteJust clean it

Rule of thumb: if a dot is black on a white screen it is most likely dead; if it is a colored dot on a black screen it is stuck, and stuck pixels are the ones worth trying to fix.

How to fix a stuck pixel

A stuck pixel is frozen on one color but still receives power, so rapidly flashing colors at it can shake the liquid-crystal cell back into normal operation. This is exactly what the Run stuck-pixel fixer button does — it cycles intense red, green, blue, white and black many times per second over a movable box you position on the defect.

  1. Locate the stuck pixel using the solid-color test above and remember its position.
  2. Launch the fixer and drag the flashing box so it sits directly over the stuck pixel.
  3. Let it run for 10–30 minutes. Many stuck pixels recover within this window; stubborn ones may need a couple of sessions.
  4. Optional gentle pressure: with the fixer running, press the exact spot through a soft, slightly damp cloth for a few seconds. Never press hard — too much force can damage more pixels.

If a pixel is truly dead (black on every color, no power) flashing will not help — but it costs nothing to try, and the fixer revives a large share of genuinely stuck pixels.

Works on monitors, laptops, TVs and phones

The test simply fills the display with color, so it runs anywhere a browser does — no app, no extension, no download:

Checking other hardware too? Try our webcam test, keyboard tester and mic test to verify a whole device at once.

Dead pixel test FAQ

How do I test my screen for dead pixels?
Click Start full-screen test and step through the solid colors. On a white screen a dead pixel shows as a tiny black dot; on a black screen a stuck pixel shows as a bright colored dot. Cycle red, green, blue, white and black, because a defect that hides on one color is obvious on another. A magnifier or your phone camera makes them easier to find.
What is the difference between a dead pixel and a stuck pixel?
A stuck pixel is powered but locked on one color — a constant red, green, blue or white dot, most visible on black. A dead pixel gets no power, so it stays black on every color and is easiest to see on white. Stuck pixels can often be revived; truly dead ones usually cannot.
Can a stuck pixel be fixed?
Often, yes. Use the built-in stuck-pixel fixer: it rapidly flashes red, green, blue and white over a movable box you place on the defect. Run it for 10–30 minutes; gentle pressure through a soft cloth with the fixer running can help too. A genuinely dead pixel, which receives no power, normally cannot be fixed in software.
Is this dead pixel test safe and free?
Yes — it is free, needs no download or sign-up, and runs entirely in your browser, only filling the screen with colors. Nothing is uploaded or installed. It works on Windows, macOS, Linux, Android and iPhone, on monitors, laptops, TVs and phones in any modern browser.
How many dead pixels are normal or acceptable?
Manufacturers follow the ISO 9241-307 standard and tolerate a small number of defective subpixels before a screen qualifies for warranty replacement — premium and Apple displays are stricter. Run this test the moment you get a new monitor or phone; documenting defects inside the return window is the best way to secure a replacement.
How do I test for dead pixels on my iPhone or Android phone?
Open this page in your phone's browser, tap Start full-screen test and raise brightness to maximum. Tap the right side of the screen to advance through the colors and inspect the glass closely. The test fills the whole display, so it behaves the same on iPhone, iPad and Android as on a desktop monitor.