Screen Test Online
39 tests for dead pixels, backlight bleeding, color banding, patterns & motion blur
Enter fullscreen mode to begin testing
Instructions
- Click or tap anywhere to go to next test
- Use ← → arrow keys to navigate
- Press ESC or click × to exit fullscreen
- Move mouse to bottom to show controls
Test Modes
Solid Colors (11)
Test for dead/stuck pixels using pure colors
Gradients (12)
Check for color banding and smooth transitions
Patterns (10)
Test screen geometry and sharpness
Motion Tests (6)
Test response time, ghosting, and refresh rate
About Screen & Monitor Test
This comprehensive screen test tool helps you identify display defects and quality issues. All tests run entirely in your browser - no downloads required and no data is sent to servers.
What This Tool Tests
Dead Pixels
Pixels that are permanently off (appear black on any color). Use white and colored backgrounds to spot them easily.
Stuck Pixels
Pixels stuck on a single color (red, green, or blue). Test with black screen to see bright dots that shouldn't be there.
Backlight Bleeding
Light leaking from edges or corners, visible on dark screens. Common on LCD/LED displays, especially at corners.
Color Banding
Visible steps in gradients instead of smooth transitions. Indicates limited color depth or panel quality issues.
Screen Uniformity
Uneven brightness or color across the display. Check with solid colors, especially gray and white.
Motion Blur & Ghosting
Trailing shadows or blur behind fast-moving objects. Common on displays with slow response times.
Gradient Test Guide
Gradient tests help identify color banding, gamma issues, and the display's ability to render smooth color transitions.
Black-White Gradients
Tests grayscale transitions. Look for visible steps or bands instead of smooth gradients - indicates limited bit depth or poor calibration.
Color Gradients (RGB)
Tests individual color channel transitions. Each color should transition smoothly from dark to bright without banding.
Dark & Bright Tone Tests
Tests shadow and highlight detail. Can you distinguish all gray levels in the 0-25% and 75-100% ranges?
Gamma & Step Tests
Gamma test checks display calibration. Step gradient shows discrete levels - each step should be clearly distinguishable.
Pattern Test Guide
Pattern tests help verify screen geometry, pixel alignment, sharpness, and scaling accuracy.
Grid Patterns
Lines should appear perfectly straight without waviness. Check for moiré patterns or interference at the fine grid level.
Checkerboard Patterns
Tests pixel response and alignment. Fine checkerboard can reveal ghosting issues. Pattern should appear uniform without flickering.
Text Sharpness
Displays sample text at various sizes. Text should be crisp and clear without fringing or blur. Tests subpixel rendering.
Color Bars & Lines
Tests color accuracy and line rendering. Horizontal and vertical lines should have consistent thickness across the screen.
Motion Test Guide
Motion tests evaluate response time, ghosting, and refresh rate performance - crucial for gaming and video.
UFO Test
A moving UFO shows motion clarity. Objects should appear sharp without blur trails. Compare different areas of the screen.
Ghosting/Chase Test
A moving object leaves trails if response time is slow. Watch for ghost images following the main object.
Scroll Test
Tests smoothness of scrolling content. Text should move fluidly without judder or stuttering.
Pixel Response Test
Alternating black/white pattern tests pixel transition speed. Should appear as uniform gray - visible flickering indicates good response.
How to Use
- Click "Start Test" to enter fullscreen mode
- Clean your screen before testing for accurate results
- Dim room lighting to better see defects
- Click anywhere or use arrow keys to cycle through tests
- Look carefully at each test pattern for anomalies
- Press ESC to exit when finished
Color Test Guide
- Black: Reveals stuck pixels (bright dots) and backlight bleeding
- White: Shows dead pixels (black dots) and screen uniformity
- Red/Green/Blue: Tests individual subpixels for stuck pixels
- Cyan/Magenta/Yellow: Additional subpixel combination tests
- Gray: Best for checking uniformity and clouding (DSE)
Testing Tips
- Test a new monitor within the return period to check for defects
- Use auto-advance mode for hands-free testing
- Works on monitors, laptops, TVs, tablets, and phones
- For accurate results, set display to native resolution
- Disable any color profiles or night mode during testing
Frequently Asked Questions
Can dead pixels be fixed?
Dead pixels are usually permanent hardware defects. Some stuck pixels may be fixable using pixel-exercising techniques (rapidly cycling colors), but true dead pixels cannot be repaired without panel replacement.
How many dead pixels is acceptable?
Most manufacturers allow 1-5 dead pixels in their warranty policy. However, for premium monitors, zero-dead-pixel guarantees are sometimes offered. Check your warranty terms and test during the return period.
Why does my screen look different at various angles?
This is due to viewing angle limitations, common on TN panels. IPS and VA panels offer better viewing angles. Some color shift at extreme angles is normal for all LCD technologies.
What causes motion blur on my monitor?
Motion blur is caused by slow pixel response times. LCD pixels need time to transition between colors. Gaming monitors with lower response times (1-5ms) will show less blur than office monitors (5-15ms).
Is backlight bleeding a defect?
Minor backlight bleeding is common on LED-backlit LCDs and isn't always a defect. However, severe bleeding that affects viewing experience may be grounds for return. Test in a dark room to assess severity.
Why do some tests look different on my phone vs computer?
Different displays use different panel technologies, color profiles, and resolutions. OLED phones have perfect blacks while LCD monitors may show backlight glow. Each display type has its own characteristics.
Related Tools
Color Picker & Converter
Convert colors between HEX, RGB, HSL, CMYK, YCbCr, Lab formats, generate color palettes, and check WCAG contrast
Color Palette Generator
Professional color palette generator with color mixing, gradient creation, color schemes, and export to CSS/SCSS/JSON formats
Timer & Stopwatch
Online stopwatch, countdown timer, pomodoro timer, and interval timer with lap recording, alarm sounds, and fullscreen mode
QR Code Generator
Generate custom QR codes for text, URL, WiFi, vCard, email, SMS and more