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Dead pixel test

Check a new laptop, monitor or phone for dead pixels and light leaks while you can still return it.

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Check every pixel

Your screen turns black, white, red, green, blue and grey. A dot that stays dark or one colour is a dead or stuck pixel. Tap, swipe or press the arrow keys for the next colour; Esc to stop.

Refresh rate

–Hz

Measuring…

480 px/s
Resolution
–
Pixel ratio
–
Browser window
–
Colour depth
–
Colour range
–
HDR
–

More screen tests

Stuck pixel fixer

Flashing light warning. The fixer flashes bright colours very fast. It can cause seizures in people with photosensitive epilepsy. Do not look at it; place it over the stuck pixel and look away or leave the room.

A man in his home office, a big computer monitor glowing on the desk behind him

For new and used screens

Every pixel, bright and true

New monitor day. Check for dead pixels while the box is still here.

BeforeStare at a screen and hope there are no dots

With sdevFull colours, one tap each, any flaw shows

  • People browsing in a busy shop

    Buying a used one

    One full-colour test before you pay.

  • A woman writing notes with a laptop on her lap

    Study laptop

    Smooth and clear for long nights of reading.

How to check your screen for dead pixels

  1. Clean the screen

    Wipe off dust first, so a speck is not mistaken for a pixel. Turn brightness up.

  2. Start the dead pixel test

    Press Start dead pixel test to fill the screen. Tap, swipe or use the arrow keys for the next colour. Backlight bleed, colour bands, sharpness and motion tests are below.

  3. Check the results

    Note any dots, light patches or stripes. Your refresh rate and screen details are shown at the top.

Good to know

  • Use the arrow keys, a tap or a swipe to change colours. Press Esc to leave full screen.
  • A dust speck moves when you wipe it; a dead pixel never does. Use a soft dry cloth.
  • Check backlight bleed in a dark room with brightness high. Look at the corners and edges.
  • The refresh rate shown is what your browser draws at. Laptops may drop to 60 Hz on battery.
  • For the stuck pixel fixer, run it 10 to 20 minutes, then check again with the red, green and blue screens.

Where people use it

  • New laptop, phone or monitor

    Check for dead dots in the first days, while you can still return it.

  • Buying a used phone

    Run full-screen colours to spot marks, dead dots and uneven light.

  • A small stuck dot

    Try the stuck pixel fixer, which flashes colours on that spot.

  • Gaming monitor check

    See the real refresh rate and watch moving blocks for smearing.

Why this one

It puts every common screen check in one place, with a stuck pixel fixer and a clear safety note before any flashing.

  • Full-screen colours for dead and stuck pixels.
  • Backlight bleed, colour bands and sharpness checks.
  • Shows resolution, pixel ratio and HDR support.
  • Works on phones, tablets and computers.

What you can change

  • Test colour
  • Motion speed
  • Stuck pixel fixer

People find this page by searching

  • dead pixel test
  • screen pixel test
  • pixel test laptop
  • monitor pixel test
  • screen test
  • stuck pixel fixer
  • backlight bleed test
  • monitor test
  • refresh rate test
  • check new laptop screen
  • phone screen test
Cite this tool
  • APA
    sdev.in. (n.d.). Dead pixel test [Web tool]. https://www.sdev.in/tools/dead-pixel-test
  • MLA
    "Dead pixel test." sdev.in, https://www.sdev.in/tools/dead-pixel-test.
  • Chicago
    sdev.in. "Dead pixel test." https://www.sdev.in/tools/dead-pixel-test.
  • BibTeX
    @misc{sdev-dead-pixel-test,
  title = {Dead pixel test},
  author = {{sdev.in}},
  howpublished = {\url{https://www.sdev.in/tools/dead-pixel-test}},
  note = {Web tool}
}

Questions people ask

How do I check my screen for dead pixels?

Press Start dead pixel test. The whole screen fills with one colour. Look closely at every part of the screen, then tap or press the arrow key for the next colour. A dead pixel stays black on every colour. A stuck pixel stays one bright colour, like red or green.

What is the difference between a dead and a stuck pixel?

A dead pixel gets no power and is always black. A stuck pixel has one colour part stuck on, so it shows as a red, green, blue or white dot. Stuck pixels can sometimes be fixed; dead pixels usually cannot.

Can a stuck pixel be fixed?

Sometimes. The pixel fixer flashes colours quickly over the spot for 10 to 20 minutes, which can wake the stuck part up. It does not always work, and it cannot fix a dead pixel. Read the flashing light warning before you start.

How do I check my monitor's refresh rate?

This page measures it as soon as it opens and shows it at the top, for example 60, 120 or 144 Hz. If you paid for a 144 Hz monitor but see 60 Hz, set the refresh rate in your display settings and use a cable that supports it.

What is backlight bleed?

Light leaking around the edges of an LCD screen. Open Backlight bleed in a dark room with brightness high. Small glow at the corners is common; big bright patches are a fault you can report under warranty.

Why do I see stripes in the gradient test?

Visible steps in a smooth ramp are called banding. Some is normal on cheaper 6-bit screens, with night light or blue light filters on, or in power saving mode. Strong banding on a new screen may mean a low colour setting.

Is my screen HDR or wide colour?

The Your screen panel shows what the browser reports: HDR, colour range (standard, wide P3 or very wide) and colour depth in bits. HDR may only show when HDR is switched on in your system display settings.

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