🔍 Dead Pixel Test
Check your screen for dead or stuck pixels with full-screen solid colors. No ads during the test — just pure colors.
Check your screen for dead or stuck pixels by cycling through full-screen solid colors: red, green, blue, black, and white. Tap, click, or use arrow keys to advance between colors while inspecting for pixels that stay dark (dead) or stuck on a single color. Double-tap or press Escape to exit. No ads interrupt the test — only pure color fills for reliable inspection.
Quick start
- 🎨 Tap or click to cycle through Red → Green → Blue → Black → White
- 🔍 Inspect each color closely for dead or stuck pixels
- ⌨️ Use arrow keys to move between colors
- 🖱️ Double-tap or press Escape to exit the test
- 📱 Works great on mobile — just tap the screen
📋 When to Use the Dead Pixel Test
Run it the moment you unbox a new screen — phone, tablet, laptop, monitor, or TV — while you're still inside the return or exchange window. A single bright stuck pixel is far easier to act on in week one than after the policy lapses. It's just as useful before buying second-hand or refurbished gear: ask the seller to run it, or check it yourself the instant you take delivery.
It also helps when you've spotted a suspicious dot and want to know what you're dealing with. A speck that vanishes when you wipe the screen is dust; one that stays put on a solid color is a pixel fault — and this test tells you which kind, which decides whether it's worth attempting a fix or filing a warranty claim.
⚙️ How the Dead Pixel Test Works
Every pixel on your screen is actually three sub-pixels — one red, one green, one blue — sitting side by side, and your eye blends them into a single color. A full-screen pure color drives just one set of sub-pixels to maximum: an all-red screen lights only the red sub-pixels, an all-green screen only the green, and so on. By flooding the display with one flat color at a time, the test strips away the visual noise that normally hides a faulty sub-pixel, so any pixel misbehaving against that field jumps out.
The pattern of the fault tells you its type. A dead pixel gets no drive at all — it stays black on every color, so it's easiest to catch on a white screen as a tiny dark dot. A stuck pixel has one or more sub-pixels locked on; it shows as a fixed red, green, or blue dot and stands out most on a contrasting field — a stuck red sub-pixel screams against green, blue, or black. A hot pixel is stuck fully on across all three sub-pixels, glowing white even on a black screen. Cycling red, green, and blue separately lets you pin down exactly which sub-pixel is at fault.
Screen technology changes what you'll see. On an LCD the backlight is always on, so even "black" is faintly lit and a dead pixel reads as a small dark patch. On an OLED each pixel makes its own light, so black pixels are genuinely off — a fully dead OLED pixel is invisible against a black screen and only shows up on white or color, which is exactly why cycling every color matters. For a reliable check, run the test fullscreen at maximum brightness in a dim room, and wipe the screen first so dust and smudges don't masquerade as faults.
How to Use the Dead Pixel Test
- Click 'Start Fullscreen Test' to enter fullscreen mode for the most accurate results.
- Click or tap the screen to cycle through solid colors: white, black, red, green, blue, and more.
- Inspect each color screen carefully for any stuck or dead pixels that appear different from the background.
- Press Escape or click the exit button to leave the test when finished.
Frequently Asked Questions
What's the difference between a dead, stuck, and hot pixel?
A dead pixel receives no power and stays black on every color — spot it on a white screen. A stuck pixel has one or more sub-pixels locked on, showing a fixed red, green, or blue dot that's clearest against a contrasting color. A hot pixel is stuck fully on and glows white even on black. The distinction matters: stuck and hot pixels can sometimes be revived, while a truly dead pixel almost never recovers.
Can I fix a stuck or dead pixel?
Sometimes — for stuck pixels, not dead ones. Rapidly cycling colors over the spot can occasionally jolt a locked sub-pixel back to life, and very gentle pressure on the exact spot (through a soft cloth, with the screen off) sometimes frees a mechanically stuck one. Neither is guaranteed, and pressing hard can cause permanent damage, so be careful. A dead pixel is a hardware failure of the pixel's transistor and realistically can't be fixed.
How many dead pixels before I can claim a warranty replacement?
There's no universal number — each manufacturer sets its own threshold, often described using ISO pixel-defect classes. Bright stuck-on dots are usually treated more strictly than dark dead ones, and a single defect near the center of the screen is more likely to qualify than several at the edges. Check your specific maker's dead-pixel policy, and act inside the return window, where retailer "zero tolerance" policies are often more generous than the warranty.
Why test on white and black separately?
They reveal opposite faults. A white screen exposes dead and dark pixels as black specks; a black screen exposes hot and stuck-bright pixels as glowing dots. Running pure red, green, and blue in between then isolates which individual sub-pixel is failing. Skipping any of these can let a fault hide.
Does it behave differently on OLED versus LCD?
Yes. On LCD the backlight never fully switches off, so a dead pixel looks like a small dark dot even on black. On OLED, black pixels are completely off, so a dead OLED pixel disappears against black and only appears on white or color — making the full color cycle essential. OLEDs are also prone to burn-in, which looks like a faint persistent image rather than a single bad pixel.
How should I set up for the most reliable test?
Run it fullscreen at maximum brightness in a dimly lit room, and clean the screen first so dust or smudges aren't mistaken for pixel faults. Look at each color from straight on and up close. If a dot moves or wipes away, it's debris; if it stays fixed in place across colors, it's a pixel.