Dead Pixel Test FAQ
Everything you need to know about running a free online dead pixel test and fixing stuck pixels on any screen.
Q. What is the best way to run a dead pixel test online free?
Open our dead pixel tester in your browser, click any color tile to enter fullscreen, then cycle through pure black, white, red, green and blue. Scan slowly for any dot that does not match the background. Dim the room and clean the screen first so dust isn't mistaken for a defect.
Q. How do I know if I have a dead pixel or a stuck pixel?
A dead pixel is completely black on every color. A stuck pixel is bright in one specific color (red, green or blue) on a black background. A hot pixel is white on black. Our free online dead pixel test reveals all three using pure full-screen colors.
Q. How do I test my monitor for dead pixels?
Set your monitor to its native resolution and normal brightness, then run full-screen white, black, red, green and blue tests. White makes black dead pixels easiest to see; black exposes hot and stuck pixels; pure red, green and blue isolate a single stuck sub-pixel. Inspect the whole panel corner to corner, giving each color 30-60 seconds.
Q. Can I fix a stuck pixel?
Sometimes. Rapidly cycling between pure red, green and blue for 20-30 minutes can revive a stuck sub-pixel - that's exactly what our stuck pixel fixer does. Gentle pressure through a soft cloth on the pixel while cycling can also help. Truly dead pixels usually require hardware replacement.
Q. How do I test an OLED TV or monitor for dead pixels?
Run the same full-screen color tests, but take a little extra care: OLED and QD-OLED panels can show temporary pixel-refresh or pixel-shift artifacts that aren't dead pixels, and some have a triangular sub-pixel layout that causes text fringing. A true dead or stuck pixel stays fixed in the same spot across every test color and input.
Q. What's the difference between backlight bleed and a dead pixel?
Backlight bleed (and IPS glow or clouding) is uneven lighting that shows as a glowing patch - usually in the corners - on a black screen, and it shifts with viewing angle. A dead or stuck pixel is a single tiny fixed dot in an exact spot that looks the same from every angle. Use our backlight uniformity test to check for bleed and the solid-color test to find individual pixels.
Q. Does this tool work on phones, tablets and 4K monitors?
Yes. The dead pixel test online is fully responsive - it works on iOS, Android, iPadOS, Windows, macOS and Linux, at any resolution from 720p up to 4K and 8K. The same tool checks an iPhone, a 4K gaming monitor or a MacBook.
Q. Can dead pixels appear or develop over time?
Yes. A panel can pass a dead pixel test at the factory and still develop dead or stuck pixels months later as transistors or sub-pixels fail. It's worth re-testing a screen periodically, especially on an OLED display or a monitor used for long daily sessions.
Q. How do I document dead pixels for a warranty or return claim?
Run the solid-color test, photograph the defect on the matching background (white for a black dead pixel, black for a hot/stuck pixel), and note the pixel's location. Take a screenshot too - if the dot is absent in the screenshot, it confirms a hardware defect rather than a software issue. Include the photos, serial number and purchase date with your claim.
Q. Is deadpixeltester.com really free?
Yes. No signup, no download and no watermarks. The fullscreen test runs locally in your browser and nothing is uploaded.
Q. How many dead pixels are acceptable under warranty?
Most manufacturers follow ISO 9241-307 class II, which tolerates a small number of sub-pixel defects. Premium 'zero bright pixel' policies, common on high-end monitors from Dell, ASUS, Apple and Samsung, allow zero bright defects. Use our test to document defects before contacting support so you can prove what you're seeing.