Dead Pixel Test
Test monitors, phones, tablets, and TVs for dead pixels, stuck pixels, and screen defects. Cycle through colors automatically or manually to reveal pixel problems before your warranty expires.
Test Settings
Test includes 9 solid colors: Black, White, Red, Green, Blue, Cyan, Magenta, Yellow, and Gray.
Current Test Color: Black
Other Tools
What you can test for
Works on any device — monitors, laptops, phones, tablets, and TVs.
Find dead pixels
Black dots visible on every color — pixel is permanently off
Detect stuck pixels
Colored dots that refuse to change regardless of the test color
Spot hot pixels
Always-bright white dots most dramatic on black screens
Test backlight bleed
See light leaking from LCD edges during the black screen test
Verify color uniformity
Spot uneven tones and color shifts across the panel
New device quality check
Test before the return window closes — typically 14–30 days
Test used devices before buying
Sellers should allow testing — if they refuse, walk away
Document for warranty claims
Photo evidence on multiple color backgrounds strengthens claims
Mobile screen testing
Test phones and tablets with matched aspect ratios
Professional display QA
Zero tolerance standard for photo and video editing monitors
How it works
Clean your screen — dust and fingerprints easily look like dead pixels
Choose auto-cycle for a quick scan or manual mode to inspect closely
Go fullscreen and scan each color from top-left to bottom-right in strips
Document any defects with photos on multiple color backgrounds for warranty claims
What each color reveals
Black
Stuck pixels, hot pixels, backlight bleed
White
Dead pixels (black dots), stuck subpixels
Red
Cyan, blue, and green subpixel defects
Green
Magenta, red, and blue subpixel defects
Blue
Yellow, orange, and red subpixel defects
Gray
Uniformity issues and subtle dead pixels
Complete guide
Dead Pixels — Permanently Off
Dead pixels appear as tiny black dots on every test color — white, red, green, blue, and yellow. The pixel is completely non-functional and will not display any color. Dead pixels occur when transistors fail, cutting power to the entire pixel. They are most noticeable on light backgrounds where the black dot stands out sharply. Dead pixels cannot be repaired and typically require display replacement under warranty.
Stuck Pixels — Fixed Incorrect Color
Stuck pixels display one wrong color regardless of what should be shown. Common colors: bright red (green and blue subpixels off), bright green (red and blue off), bright blue (red and green off), white (all subpixels on), cyan (red off), magenta (green off), yellow (blue off). Stuck pixels are most visible on black backgrounds. Some self-correct over time; others can be fixed with software that rapidly cycles colors.
Hot Pixels & Backlight Bleed
Hot pixels remain bright white on all test colors, appearing most dramatically on black screens. More common on OLED than LCD displays. During the black screen test, also watch for bright patches around edges or corners — this is backlight bleed, not a pixel defect. LCD monitors use backlights behind the panel; imperfect seals allow light to leak through. Test in a completely dark room for accurate assessment.
Color Uniformity Issues
As you cycle through solid colors, watch for uneven tones across the display. One side appearing lighter or darker than the other indicates panel uniformity problems. Color shifts — one area appearing more blue, red, or green than another — suggest calibration defects. Uniformity issues affect professional color-critical work and may qualify for warranty replacement on professional-grade monitors.
When to Test Your Display
Test new monitors, laptops, phones, and tablets immediately — within the return period (typically 14–30 days). After it expires you are limited to manufacturer warranty policies, which often require multiple defects. Test before accepting delivery of expensive professional displays. Test immediately after repairs or warranty replacements. Always test used devices before completing a purchase — sellers should allow it.
Manufacturer Warranty Policies
Most manufacturers require 3–10 dead pixels before replacing a consumer display. Professional monitors have stricter 0–1 tolerance. Laptops typically require 3–5 dead pixels, or 1 in the center. Many warranties cover dead pixels but not stuck pixels — read your specific terms. Defects in the center viewing area are weighted more heavily than edges. Retailer return periods usually accept returns for any defect regardless of type.
Can Stuck Pixels Be Fixed?
Sometimes. Programs that rapidly cycle RGB colors can unstick pixels — success rate is 10–30%, best within the first 48 hours. Popular tools: JScreenFix (web-based), PixelHealer (Windows). Run for 20–60 minutes while monitoring the stuck pixel. Alternatively, wait — some stuck pixels self-correct after days of varied content. Gentle pressure with a soft cloth while cycling colors is a last resort with real risk of creating more damage.
Scanning Methodically
Don't just glance — systematically scan the entire screen. Start top-left, move across in horizontal strips to top-right, drop down one strip and scan back left. This grid pattern ensures you examine every area. Pixel defects are tiny — moving too quickly will miss them. Spend 10–15 seconds per color, totaling 2–3 minutes minimum. For a potential defect, cycle through multiple colors to confirm: true dead pixels appear black on all colors, stuck pixels show the same wrong color on all backgrounds.
See Also
Frequently Asked Questions
Everything you need to know about dead pixel test.