Run a fullscreen dead pixel test across 9 solid colors to find dead (dark) and stuck (bright) subpixels on a monitor, laptop or phone. Mark suspicious spots with pixel coordinates and export a report for a warranty claim.
Shortcuts in fullscreen: ←/→ or Space switch color · M mark pixel · Esc exit
Photosensitivity warning: This mode flashes red, green, blue and white at high speed in a 140×140 px square to exercise a stuck liquid-crystal subpixel. Do not use it if you or anyone in the room has photosensitive epilepsy.
Your Dead Pixel Test Result
No defective pixels marked
Colors inspected
0 / 9
Marked positions
0 marked
All checked backgrounds looked clean.
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What this dead pixel test checks
Every pixel on an LCD or OLED panel is made of three subpixels: red, green and blue (some OLED panels add a white subpixel or arrange them in a triangle). When one transistor or organic emitter fails, the defect only shows up on specific background colors. For example, a green subpixel that is stuck ON looks completely normal on a white or green screen, but glows like a neon pinprick on a pure black background. Cycling through pure black, pure white, red, green, blue and their secondary combinations (cyan, magenta, yellow) forces every subpixel both fully ON and fully OFF so nothing can hide.
Before you start
Wipe the screen with a dry microfiber cloth. Dried droplets and dust specks diffract light and look exactly like dead or rainbow pixels against a white background. If the spot moves slightly when you change your viewing angle, it is on the front coating, not inside the panel.
Set your display to native resolution and 100% browser zoom. That keeps the pixel coordinates you mark aligned with physical pixels.
Turn off Night Light, True Tone or f.lux, and raise brightness to at least 70% so faint stuck subpixels are easy to see.
How to run the test
Click Start fullscreen dead pixel test above (or click any color swatch). Your browser enters fullscreen and hides the mouse cursor after two seconds.
Scan the screen in three horizontal bands—top, middle and bottom—from about 30–40 cm (12–16 in) away.
Press → or Space to step through all nine colors: Black, White, Red, Green, Blue, 50% Grey, Cyan, Magenta and Yellow.
If you spot a defect, press M to toggle Mark Mode and click on the spot. A numbered ring and pixel coordinate are drawn around it so you can take a clear phone photo for your retailer or RMA ticket.
Press Esc to exit fullscreen and view your result card, warranty guidance and downloadable PNG report.
How to read your results (dead vs stuck vs dust)
Dead pixel (dark dot on white)All three subpixels remain unlit. Looks like a sharp square black dot on white and primary colors.Stuck subpixel (colored dot on black)One subpixel (red, green or blue) stays switched ON. Often responds to the rapid RGB flasher.Dark subpixel (dark on one color)A dead red subpixel looks black on red, cyan-tinted on white, and invisible on green or blue.Dust or droplet on coatingSoft edges with a tiny rainbow shimmer; shifts position relative to the pixel grid when you move your head.
What you see
Diagnosis
Can it be fixed?
Return / RMA advice
Bright red, green or blue pinpoint on pure black
Stuck subpixel
Sometimes (run the RGB fixer for 15–30 min)
Covered under most "Zero Bright Dot" policies on premium lines (Dell Ultrasharp/Alienware, ASUS ROG, BenQ Zowie)
Bright white pinpoint on pure black
Bright pixel defect
Rarely
Covered by nearly all bright-dot guarantees even for 1 pixel
Black dot on white, red, green and blue
Full dead pixel
No (transistor is permanently off)
ISO 9241-307 Class 1 allows 0; standard Class 2 panels often require 3–5 dark subpixels—use retailer return if within 14–30 days
Dark dot on only one primary color (e.g., black on red, cyan on white)
Single dark subpixel
Rarely
Counts as 1 dark subpixel under manufacturer tables; photograph on both white and the affected primary color
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When results can be misleading
Anti-glare grain and smudges: Heavy matte coatings on IPS gaming monitors can scatter light around a single speck of skin oil, mimicking a stuck pixel on white. Always wipe the spot gently before filing a claim.
OLED pixel shift / screen move: Modern OLED monitors shift the active image by several pixels every few minutes to reduce burn-in. A dark band along one edge is usually the reserve border, not a row of dead pixels.
Local dimming zones on Mini-LED panels: A tiny bright cursor or marker on pure black may look dimmer than expected if full-array local dimming (FALD) dims the zone around it. Turn local dimming off while inspecting pixels.
Dead pixel test vs related tests
A pixel test checks individual subpixels. If you see larger glowing patches near the corners on the black screen, that is not a pixel defect—use the backlight bleed and IPS glow test to evaluate dark-room uniformity. If faint vertical bands or posterized steps appear on gradients, open the monitor color test. And if text fringes look colored on a healthy panel, check your subpixel layout in the text clarity test.
Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel receives no power (or is permanently blocked depending on panel wiring) and stays black across white, red, green and blue backgrounds. A stuck pixel has one or more subpixels locked in the ON state, so it shines red, green, blue, cyan, magenta or yellow on a pure black screen. Stuck subpixels occasionally unstick after thermal cycling or rapid RGB switching; true dead pixels almost never recover.
How many dead pixels does it take for a warranty replacement?
Most consumer monitors follow ISO 9241-307 Class 1 or Class 2 rules. Premium series (such as Dell UltraSharp, Alienware, and many ASUS ProArt/ROG models) guarantee zero bright dots, meaning a single stuck bright subpixel qualifies for an exchange, but they still allow 3 to 5 dark subpixels. Within your first 14 to 30 days, returning or exchanging through the retailer is much easier than a warranty claim.
Does the stuck pixel fixer actually work?
It works on a minority of stuck liquid-crystal subpixels where the liquid crystal molecules are partially sluggish rather than electrically shorted. Run the flashing box over the defect for 15 to 30 minutes. If there is no change after two sessions, the transistor is electrically stuck and software flashing will not fix it.
Can I press on a stuck pixel to fix it?
We do not recommend pressing on modern thin-bezel IPS, VA or OLED panels. Concentrating pressure with a stylus or fingernail can crack the glass substrate or leave a permanent bright pressure mark that voids your warranty.
Does this dead pixel test work on phones and laptops?
Yes. Tap any color swatch to fill the screen, then swipe or tap to cycle through all 9 backgrounds. On iPhones and iPads where Safari restricts the Fullscreen API on phones, the test automatically expands to cover the browser viewport.
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