- Clean Your Screen First: Wipe away dust or smudges with a microfiber cloth so they aren't mistaken for defective pixels.
- Controls During Test: Click/Tap anywhere, use Left / Right Arrow Keys, or press Spacebar to cycle through test backgrounds.
- Dead vs. Stuck Pixels: A Dead Pixel stays permanently black on all bright backgrounds. A Stuck Pixel stays lit in a single color (red, green, blue, etc.) even on a pure black background.
- Exit Anytime: Press the ESC key or swipe/exit fullscreen on mobile devices to return to this page.
- Mouse Speed & Acceleration Test
- Mouse Drag Test
- Frame Rate Test (FPS Test)
- Sequence Memory Test
- APM Test
- Free Stroop Color Word Test Online
- Aspect Ratio Calculator
- Chimp Test
- Keyboard Double-Click Test
- Color Blind Test
- Color Memory Test
- Stopwatch Game: Time Perception Test
- Number Memory Test
- Mouse Double Click Test
- What Is My Screen Resolution
- Webcam Test
- CPS Test
- Visual Memory Test
Dead Pixel Tester: Check Your Screen for Defective Pixels
A dead pixel is a tiny dot on your screen that stays black or shows the wrong color. It’s hard to see on a busy desktop, but it stands out on a plain background. This Dead Pixel Tester fills your whole screen with one solid color at a time, so those dots are easy to find.
Use it on a new monitor, a used laptop, a second-hand display, or any screen you suspect has a fault.
What Is a Dead Pixel?
Every screen is made of thousands of tiny pixels. Each pixel is built from red, green, and blue parts. When one fails, it shows up in a few different ways:
- Dead pixel: stays black and never lights up.
- Stuck pixel: stays on one color, such as red, green, or blue.
- Bright (hot) pixel: stays white on dark backgrounds.
A solid color test is the standard way to find all three, because the defect has nothing to hide against.
What You Can Do With This Tool
Choose a starting color or pattern. The tool offers 10 test modes:
- Black
- White
- Red
- Green
- Blue
- Yellow
- Cyan
- Magenta
- Gray
- A grid pattern on a dark background
The page shows your selected mode (for example, “Pure Blue”) so you always know where you are starting.
See basic display info. The top of the page shows your resolution, pixel ratio, and color depth (for example, 24-bit).
Run the test your way. There are three buttons:
- Start Fullscreen Test: fills your screen with the selected color.
- Auto Cycle Mode: moves through the colors for you.
- How to Use: opens in-tool instructions.
Adjust the settings.
- Auto-Cycle Speed: sets how long each color stays on screen. The default is Normal (3.0s).
- Auto-hide mouse cursor in test: keeps the cursor from covering a pixel while you inspect the screen. It’s on by default.
How to Test Your Screen for Dead Pixels
- Clean your screen first. Use a soft, dry microfiber cloth. Dust and smudges can look like dead pixels.
- Pick a starting color. Select any color box. Black is a good first choice.
- Click “Start Fullscreen Test.” The color fills the screen.
- Look closely at every area. Check the corners and edges as well as the center.
- Switch colors. Move through the full set, or click “Auto Cycle Mode” to let the tool do it.
- Note any spots. If a dot looks wrong on a few colors, it’s likely a defective pixel.
What Each Color Reveals
Different colors expose different problems, so one color is never enough.
| Test color | Best for finding |
|---|---|
| Black | Bright or stuck pixels that glow when they shouldn’t |
| White | Dead pixels that appear as dark dots |
| Red, Green, Blue | Stuck pixels in a single color channel |
| Yellow, Cyan, Magenta | Color mixing problems that primary colors can miss |
| Gray | General check of how the screen looks on a mid-tone |
| Grid pattern | Visual reference across the screen on a dark background |
Tips for Better Results
- Dim the room. Pixel defects are easier to spot in low light, especially on black.
- Look up close. A single pixel is tiny. Move your face closer to the screen.
- Check every color. A pixel can look fine on white and fail on red.
- Slow down auto-cycle if needed. If 3 seconds feels too fast to scan the whole screen, change the Auto-Cycle Speed setting.
- Test more than once. Run the test again on another day to confirm what you saw.
When to Use a Dead Pixel Test
- Buying a new monitor or laptop: test it soon after unboxing, while a return is still easy.
- Buying a used screen: check before you pay.
- Checking a warranty issue: record which colors showed the defect.
- Troubleshooting odd spots on your screen: find out whether they are pixel defects.
- Regular maintenance: run a quick check if your display has been dropped or pressed.
Frequently Asked Questions
How can I tell a dead pixel from dust on my screen?
Dust and smudges usually look fuzzy and may move or disappear when you wipe the screen. A dead pixel is a sharp, tiny square that stays in the exact same spot on every test color.
Does this tool fix dead pixels?
No. It only helps you find them. A truly dead pixel usually can’t be repaired, though stuck pixels sometimes go away on their own.
Why does the tool hide my mouse cursor?
A cursor can sit on top of a small defect and hide it. The auto-hide option keeps the screen clear while you inspect it. You can turn it off by unchecking the box.
How many dead pixels are acceptable?
It depends on the manufacturer. Many brands have their own policy on how many defective pixels are covered by a warranty. Check your brand’s policy, and write down what you found before contacting support.
I found one stuck pixel. Is my screen broken?
Not necessarily. A single pixel rarely affects everyday use. Whether it counts as a warranty defect depends on the manufacturer’s policy and where the pixel is.