A dead pixel test fills your screen with one pure color at a time, so a pixel that does not light up, or one that is stuck on a single color, stands out right away. The HypestKey dead pixel test runs in your browser, uses six colors (black, white, red, green, blue and gray) and takes about two minutes for a full check.
What is a dead pixel test?
A dead pixel test is a quick screen check that shows six solid colors in full screen, one after another. A 1920 × 1080 monitor has 2,073,600 pixels and a 4K panel has 8,294,400, so a single faulty dot is easy to miss on a busy desktop. On a flat color it jumps out in seconds.
Run it on a new monitor, laptop or TV on the first day, while you can still return it. Run it again on a used screen before you pay for it.
How to use the dead pixel test
- Wipe the screen with a dry microfiber cloth so dust does not look like a bad pixel.
- Set the brightness to maximum and sit at your normal viewing distance.
- Click Start test. The first color fills the whole screen and the mouse cursor hides.
- Switch colors with a click, a tap, the arrow keys or Space. The left arrow goes back.
- Scan each color slowly from corner to corner, in strips, including the edges.
- Press Esc (or Exit on a phone) to stop, or step past gray to finish the test.
- If you see a dot, note its color and position and take a photo of it.
What is the difference between a dead pixel and a stuck pixel?
A dead pixel never lights up, so it shows as a black dot on every color and is easiest to see on white. A stuck pixel has one or two of its three subpixels (red, green, blue) always on, so it shows a fixed colored dot. It stands out most on black. A hot pixel is stuck fully on and stays white.
The difference matters. A stuck pixel still gets power and can sometimes be woken up again. A dead pixel usually means the transistor that drives it has failed, and software cannot fix that.
Which colors does the dead pixel test use, and what does each one show?
The test uses six colors because each one hides some defects and shows others. Black reveals stuck and hot pixels, white reveals dead pixels, and red, green and blue each check one subpixel channel. Gray at 50% shows uneven backlight and faint dark spots that the bright colors can hide.
| Color | Value | What to look for |
|---|---|---|
| Black | #000000 | Bright or colored dots (stuck and hot pixels), backlight bleed at the edges |
| White | #FFFFFF | Black dots (dead pixels), dust under the panel |
| Red | #FF0000 | Dark dots where the red subpixel is dead, green or blue dots that are stuck |
| Green | #00FF00 | Dark dots where the green subpixel is dead, red or blue dots that are stuck |
| Blue | #0000FF | Dark dots where the blue subpixel is dead, red or green dots that are stuck |
| Gray | #808080 | Uneven brightness, clouding and faint spots |
How many dead pixels are acceptable on a new monitor?
There is no single legal number. The old ISO 13406-2 standard set four classes per million pixels: Class I permitted zero faults, Class II up to 2 bright, 2 dark and 5 subpixel faults. Under Class II a 4K screen (8.3 million pixels) could still pass with about 16 bright pixels.
| ISO 13406-2 class | Always-on pixels | Always-off pixels | Subpixel faults |
|---|---|---|---|
| Class I | 0 | 0 | 0 |
| Class II | 2 | 2 | 5 |
| Class III | 5 | 15 | 50 |
| Class IV | 50 | 150 | 500 |
Numbers are per million pixels. ISO 13406-2 was withdrawn in 2008 and replaced by ISO 9241-307, and today most makers publish their own pixel policy (see the defective pixel overview). Some premium lines promise a swap for a single bright pixel, while budget models often need several. Check the policy for your exact model before you decide.
Can you fix a stuck or dead pixel?
A stuck pixel sometimes recovers on its own, or after a few minutes of fast color flashing on that spot, or after very light pressure with a soft cloth while the screen is on. A truly dead pixel almost never comes back, because the part that powers it has failed. Nothing here is guaranteed.
Do not press hard. Too much pressure can damage more pixels or crack the panel, and it may void the warranty. If a dot appears and stays after a fall or a hit, the panel itself is damaged and needs service.
What should you do if you find a dead pixel?
Write down the color it showed, its position and the date, and take a clear photo with the test color behind it. If the screen is new, contact the store first: in the EU you can return most online purchases within 14 days without giving a reason, and many shops elsewhere offer 14 to 30 days.
After that window, the maker’s warranty and pixel policy decide. Count how many dots you found and compare that with the policy. Laptops and phones follow the same steps, but the repair is usually a full panel swap.
How this tool works
When you press Start, HypestKey asks your browser to show one color layer in full screen with the Fullscreen API. Each color is a pure sRGB value, so every pixel on the panel gets the same signal. The cursor hides, and the short hint fades after three seconds so it covers no pixels.
Where full screen is not available, such as Safari on iPhone, the color layer covers the whole browser window instead and the address bar stays visible. Scroll it away or check that strip again in another app. The tool also shows your screen size in physical pixels (CSS pixels multiplied by the display scale), so you can see how many pixels you are checking. Nothing is uploaded: the test is plain HTML and JavaScript running on your device.
The limits are simple. A browser cannot read the state of a pixel, so the test only shows the colors and your eyes do the checking. Your graphics driver, night light, HDR or color profile can shift the shades a little, which does not change the result. Turn off blue light filters for the check.
Does the dead pixel test work on laptops, phones and TVs?
Yes. The dead pixel test works on any screen that can open a web page: desktop monitors, laptops, tablets, phones and smart TVs with a browser. On a phone, tap to switch colors and tap Exit to leave. On a TV, use the arrow keys on the remote if its browser passes them to the page.
Setting up a new PC? Check the rest of it too: the keyboard tester finds dead keys, the mouse polling rate test shows how often your mouse reports, and the FPS calculator estimates frame rates for your new display. Our guide to installing Windows 11 on a new PC covers the next step, and all checks live on the HypestKey tools page.