Free Online Screen
Testing Tools
Test your screen for dead pixels, backlight bleed, color accuracy, refresh rate, and more — directly in your browser, no download required.
Free Online Screen Tester
Click any color to enter fullscreen. Use arrow keys to cycle. Press F for fullscreen, Esc to exit.
- Switch color
- ← →
- Fullscreen
- F
- Exit
- Esc
TV users can use remote arrow keys
Pixel-Level Precision
Multi-color fullscreen frame-by-frame scanning to precisely locate bright spots, dark spots, and stuck pixels.
Color & Greyscale Analysis
Full-spectrum testing covering color accuracy, gamut, greyscale, banding, and depth.
25+ Test Tools
Dead pixels, backlight bleed, greyscale, color accuracy, gamut, refresh rate, ghosting, blooming, HDR and more.
Free · No Download
Runs entirely in your browser. Phones, tablets, laptops, monitors, TVs — any device with a screen.
Three steps to a verified screen
Choose a Test Tool
Pick from dead pixel, backlight bleed, color accuracy, or any of the 20+ tools. Beginners: start with the dead pixel test — it's step one of any screen inspection.
Go Fullscreen
Press F11 or click the fullscreen button. Pure color patterns cover the entire screen. Use arrow keys to cycle colors and inspect every region.
Review & Decide
Document defects with photos. Compare against the manufacturer's pixel policy or the retailer's return window. Most defects qualify for return within 14-30 days.
Most popular screen tests
These are the most-used screen tests, in order: dead pixel test (the starting point for any inspection), backlight bleed test (essential for dark-room movie watching), color accuracy test (for photo and video work), refresh rate test (to verify your panel runs at its rated Hz), and burn-in test (for OLED owners).
Dead Pixel Test
Solid-color fullscreen frame-by-frame scan. Detects bright pixels, dark pixels, and stuck pixels in seconds.
Open toolBacklight Bleed Test
Pure black fullscreen in a dark room to detect LCD backlight leakage and IPS glow.
Open toolGreyscale Test
256-level greyscale transition check. Reveals shadow crushing, highlight clipping, and color banding.
Open toolColor Accuracy Test
Standard color patch comparison for bias diagnosis. Verify your screen reproduces colors faithfully.
Open toolColor Gamut Test
sRGB and DCI-P3 hidden pattern gamut test. Verify your panel's wide gamut claims instantly.
Open toolRefresh Rate Test
Real-time frame rate detection. Verify your panel runs at its rated 60Hz, 120Hz, 144Hz, or 240Hz.
Open toolGhosting Test
Moving block test for response time and grey-to-grey transition speed. Catch slow pixel response.
Open toolBurn-in Test
OLED and AMOLED burn-in detection. Solid color, checkerboard, and gradient scan modes.
Open toolSolid color screens
Fullscreen colors for pixel testing, ambient lighting, and chroma key use. Click any swatch to launch.
Find the right test, fast
Browse tools by category: color quality (accuracy, gamut, gradients, uniformity), performance (refresh rate, ghosting, tearing, HDR), colors (solid fullscreen colors), calibration (gamma, brightness, contrast), and calculators (screen size, aspect ratio).
Color Quality
Accuracy, gamut, gradient, and uniformity tests for calibrated viewing.
Performance
Refresh rate, ghosting, tearing, and motion clarity diagnostics.
Solid Colors
Fullscreen colors for pixel testing and ambient lighting use.
Calibration
Gamma, brightness, contrast, and full color calibration workflows.
Calculators
Screen size, aspect ratio, and pixel density utilities.
Device Tests
Step-by-step inspection guides for every device category.
Tailored guides per device
Different devices have different testing priorities. Laptops need a full panel check (the panel lottery is real). Phones need OLED burn-in and touch-dead-zone checks. TVs need backlight bleed and HDR verification. Our device guides walk you through the right inspection flow for each.
Laptop Screen Test
8-step standard screen verification · Panel type comparison · Return standards · Parameter glossary
Monitor Screen Test
IPS/VA/OLED panel testing · PPI verification · G-Sync/FreeSync validation
OLED Screen Test
Burn-in · PWM · ABL · Black crush — comprehensive OLED-specific issue coverage
LCD Screen Test
IPS bleed · VA ghosting · Mini LED blooming — complete LCD panel evaluation
Mobile Screen Test
OLED burn-in · Touch dead zones · PWM flicker — essential for used phone inspection
TV Screen Test
Mini LED blooming · Backlight bleed · OLED burn-in · MEMC · HDR evaluation
Six rules for accurate results
Follow these guidelines to avoid false positives and missed defects during your screen inspection.
Warm Up 15-30 min
Cold panels hide defects. Let your monitor reach operating temperature before testing.
Disable Enhancements
Turn off sharpness boost, dynamic contrast, motion smoothing — they mask real defects.
Use Native Resolution
Non-native scaling introduces artifacts that look like pixel defects but are not.
Use Proper Cables
For 4K 144Hz, use DisplayPort 1.4 or HDMI 2.1. Older cables limit refresh rate.
Dark Room for Bleed
Backlight bleed is invisible in ambient light. Test in a dark room for accurate results.
Judge at Normal Distance
Getting too close reveals subpixel structure that is normal, not defective.
Frequently asked questions
Everything you need to know about testing your screen with ScreenTestLab.
Pixel-perfect precision for every screen.
Start testing your screen now — no download, no signup, no cost. Just open a tool and go fullscreen.