Screen Test — Free Online Monitor Test Patterns

Run 6 professional test patterns in fullscreen to check your monitor for backlight bleed, banding, color accuracy, and uniformity issues. Works on any screen — no download needed.

6 Test Patterns 100% Free Runs in Browser

Choose a Test Pattern

Click any pattern to launch it in fullscreen, or start the full test to cycle through all six automatically.

Instructions: Click a pattern card to view it fullscreen. Use Space or Arrow keys to cycle through patterns. Press Esc to exit. For best results, set brightness to 100% and test in a dimly lit room.

What Each Pattern Tests For

Each of the six screen test patterns targets a specific type of display issue. Knowing what to look for makes the difference between catching a defect and missing it.

Horizontal & Vertical Gradients

Smooth black-to-white transitions expose banding artifacts where your monitor displays abrupt tonal steps instead of seamless gradients. Common on 6-bit and low-end 8-bit panels.

Checkerboard

Alternating black and white 32px squares test pixel response time and sharpness. Blurry edges or ghosting mean slow response — a concern for fast-moving content and gaming.

Gray Uniformity

Five columns of gray (20% to 80%) reveal backlight bleed, IPS glow, and clouding. Bright spots along the edges or corners indicate light leaking through the panel frame.

Color Bars

Eight standard bars (white, yellow, cyan, green, magenta, red, blue, black) check color accuracy and white balance. Compare against a reference image to spot tinted or washed-out hues.

1px Grid

A fine grid of lines spaced 2 pixels apart tests sub-pixel rendering and native resolution sharpness. Moire patterns or uneven line thickness mean your display is scaling incorrectly.

Full Cycle Test

Runs all six patterns in sequence so you can evaluate your screen comprehensively without switching manually. Ideal for a quick pre-purchase or warranty inspection.

Backlight Bleed Test

Backlight bleed is one of the most common LCD defects. It appears as uneven brightness along the edges or corners of your screen, especially visible on dark scenes in movies, games, or photo editing. IPS glow — a wider, more diffuse bright area that shifts when you change viewing angles — is a related but separate issue.

To test for backlight bleed, click the Gray Uniformity pattern above and switch to the 20% or 40% gray columns. Then:

  1. Set your screen brightness to 100%.
  2. Darken the room as much as possible.
  3. Look at the edges and corners — any bright patches are backlight bleed.
  4. Shift your viewing angle side to side. If the glow follows your eyes, it is IPS glow (normal on IPS panels).

Some backlight bleed is expected on all edge-lit LCDs. It only warrants a return if the bleed is visible during normal use at standard brightness — see our warranty guide for manufacturer policies.

More Display Tests

The screen test is one part of a thorough display check. Use these companion tools for a complete evaluation.

Dead Pixel Test Check for dead and stuck pixels with solid color screens Stuck Pixel Fixer Flash rapid colors to revive stuck pixels Burn-In Test Detect ghost images on OLED and LCD screens Complete Guide Learn the difference between dead, stuck, and hot pixels