Free Online Device Test
Free Dead Pixel Test
Display full-screen solid colours to find dead, stuck or hot pixels on a monitor, laptop, tablet or phone screen.
Works on compatible computers, tablets and mobile devices. No browser permission is required.
Check Your Screen for Bad Pixels
Choose a colour, enter full screen and inspect the entire display carefully.
Clean the screen before testing
Dust and fingerprints can look like defective pixels. Clean the display gently before starting.
Start Fullscreen Test
Open the solid-colour test in full screen so the selected background covers the visible display.
Automatic colour cycle
Cycle automatically through the test colours at 1, 2, 3 or 5 second intervals.
Choose a Test Colour
Inspect the display using white, black, red, green, blue, cyan, magenta, yellow and grey backgrounds.
- White — #FFFFFF
- Black — #000000
- Red — #FF0000
- Green — #00FF00
- Blue — #0000FF
- Cyan — #00FFFF
- Magenta — #FF00FF
- Yellow — #FFFF00
- Grey — #808080
Use Any Colour
Choose a custom solid colour when you want to inspect a specific shade or brightness.
Pixel Defect Guide
- Dead pixel
- A black dot that stays dark on bright backgrounds.
- Stuck pixel
- A pixel fixed on red, green, blue or another colour.
- Hot pixel
- A bright white dot visible on dark backgrounds.
- Screen mark
- Dust or damage that changes from different angles.
No Screen Data Is Collected
This tool only displays colours in your browser. It does not take screenshots or inspect your display contents.
How to Use the Dead Pixel Test
- Clean the screen and reduce reflections.
- Press Start Fullscreen Test.
- Inspect white, black, red, green and blue.
- Use the arrows or on-screen controls to change colour.
- Check the whole screen, including the edges.
- Press Escape or Exit Test when finished.
How to Inspect the Display
View the screen normally, then move closer to inspect suspicious dots. A true pixel defect remains in exactly the same place on every colour.
Check several colours because some stuck pixels are visible only against particular backgrounds.
Dead Pixels, Stuck Pixels and Hot Pixels Explained
Pixel faults can look similar at first, but their behaviour across different solid colours helps identify the most likely type of display defect.
Dead pixel
A dead pixel usually remains black because the pixel is no longer producing visible light. It is easiest to notice on white, grey, yellow or other bright test backgrounds.
How to check: Look for a tiny black point that remains in exactly the same position as every test colour changes.
Stuck pixel
A stuck pixel or subpixel remains fixed on one colour, often red, green, blue, cyan, magenta or yellow. The dot may disappear against a matching background but return on contrasting colours.
How to check: Compare red, green and blue screens to identify which colour channel may be stuck.
Hot pixel
A hot pixel appears unusually bright, commonly as a white point on a black or dark background. It may remain visible even when the rest of the display is showing near-black content.
How to check: Use black, dark grey and custom dark colours in a dim room to make bright points easier to see.
Dust, pressure mark or screen damage
Dust, fingerprints, scratches, pressure marks and panel damage can resemble defective pixels. These marks are often larger than one pixel or change appearance when viewed from another angle.
How to check: Turn the screen off, clean it safely and inspect the same position from several viewing angles.
Why a Dead Pixel Test Uses Different Colours
A single background cannot reveal every pixel fault. Testing multiple colours changes which red, green and blue subpixels should be active, making different defects easier to isolate.
White — Find dead pixels and dark marks
A white screen activates the red, green and blue subpixels together. Black dots and darker areas are usually easiest to see against this bright background.
Black — Find hot pixels and light leakage
A black screen helps reveal bright or glowing pixels. It can also make backlight bleed, IPS glow and uneven dark-screen illumination more noticeable.
Red — Check the red subpixel channel
A red background helps identify pixels whose red subpixel is not responding correctly or pixels that remain green, blue, cyan or another contrasting colour.
Green — Check the green subpixel channel
A green test can expose missing or stuck green subpixels. Because the human eye is highly sensitive to green, small differences may be particularly visible.
Blue — Check the blue subpixel channel
A blue screen helps identify faults affecting the blue subpixel. It is also useful for spotting pixels that remain red, green or unusually bright.
Grey — Check uniformity and subtle marks
Mid-grey is useful for finding uneven brightness, faint image retention, pressure marks, dirty-screen effect and defects that are difficult to see on pure black or white.
Cyan, magenta and yellow — Compare combined colour channels
These secondary colours activate two subpixel channels at once. They can reveal faults that appear only when particular colour combinations are displayed.
Custom colour — Inspect a specific shade or brightness
Use the custom colour picker to reproduce the background where a suspicious pixel is most visible or to test very dark and very bright shades.
How to Get an Accurate Dead Pixel Test Result
Use the display at its normal operating resolution and inspect the screen at a comfortable viewing distance before moving closer to investigate suspicious points.
- Clean the display with a suitable soft cloth.
- Reduce reflections and direct glare.
- Use full-screen mode so every visible pixel is covered.
- Inspect the centre, corners and panel edges.
- Repeat the test at normal and reduced room lighting.
- Check landscape and portrait orientation on mobile devices.
One Pixel or a Larger Display Problem?
A single defective pixel is normally a very small fixed point. Larger patches, lines, flickering areas or colour bands can indicate a different display, cable, graphics or panel problem.
- A vertical or horizontal line is not usually one dead pixel.
- A mark that moves with the page may be part of the image.
- A mark visible when the display is off may be dirt or damage.
- Flickering can relate to refresh rate, power or the video connection.
- Uneven dark areas may be backlight bleed or panel uniformity.
- Temporary shadows may be image retention rather than a dead pixel.
What to Do After Finding a Suspected Bad Pixel
Confirm the defect carefully before arranging a return, repair or warranty claim. Pixel policies vary, so accurate notes and evidence can make the next step clearer.
Repeat the test
Check the same location on white, black, red, green, blue and grey. A true pixel defect remains fixed in the same physical position.
Restart and reconnect
Restart the device. For an external monitor, reconnect the power and display cable and test another compatible input or source.
Record the location
Note whether the point is near the centre, edge or corner and which backgrounds make it visible. A close photograph can help document the issue.
Check the pixel policy
Review the retailer or manufacturer warranty terms. Some policies use defect-count, colour, location or time-limit requirements.
What Dead Pixel Results Mean
A pixel that stays black may be dead. A pixel that remains red, green or blue may be stuck. A bright point visible on black can be a hot pixel.
Pixel policies differ between manufacturers. Record the location and appearance before contacting a retailer or manufacturer.
Not Sure Whether It Is a Bad Pixel?
Use these checks to separate a pixel defect from dirt, software or image retention.
Clean the screen
Turn the display off and clean it safely with a suitable soft cloth.
Check every colour
A real defective pixel stays in the same position as the colour changes.
Restart the display
Restart the device and reconnect external monitors.
Try another source
Test another browser, device or input cable if the mark changes.
Frequently Asked Questions
Is this dead pixel test free?
Yes. It is free and requires no account, download or permission.
What is the difference between a dead and stuck pixel?
A dead pixel normally remains black, while a stuck pixel remains fixed on one colour.
Can this test repair a stuck pixel?
No. This tool identifies defects. Colour-flashing repair methods are not guaranteed.
Which colours should I test?
White, black, red, green and blue are most important. Grey, cyan, magenta and yellow can reveal additional defects.
Why do I see a dot only on one colour?
A stuck subpixel may appear only against certain backgrounds because one colour channel is not changing correctly.
Can I use this on a phone or tablet?
Yes. Open the test fullscreen where supported and inspect portrait and landscape orientations.
How can I tell if a black dot is dust or a dead pixel?
Turn the display off and clean it safely. Dust is often visible on the surface or changes when viewed from another angle, while a dead pixel remains in the same lit-screen position.
Should I test a new monitor for dead pixels?
Yes. Testing a new monitor, laptop, tablet or phone early can help you identify a panel defect while the retailer's return period is still open.
Can a dead pixel appear later?
Yes. Pixel defects can be present from new or develop later because of panel ageing, electrical failure, impact, pressure or manufacturing variation.
Is one dead pixel covered by warranty?
It depends on the retailer, manufacturer and product policy. Some policies require a particular number, type or location of defective pixels.
What is a bright pixel?
A bright pixel remains illuminated when it should be dark. It may appear white or as a fixed coloured point on black and dark backgrounds.
Is image retention the same as a dead pixel?
No. Image retention appears as a temporary shadow or outline of previous content, while a dead or stuck pixel is a tiny fixed point in one location.
Can browser zoom affect the test?
The fullscreen backgrounds still cover the display, but using the browser at normal zoom and the device at its native resolution provides the clearest inspection conditions.
Does this test work on OLED, LCD and LED screens?
Yes. The solid-colour inspection method can be used on OLED phones and televisions as well as LCD or LED-backlit monitors, laptops and tablets.
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