Backlight bleed
Look for uneven bright patches around edges or corners when the room is dim.
Dark-screen diagnostics
Free Open Source Black Screen Test Online
Open a clean black screen, go full screen, and inspect your display for edge glow, backlight bleed, and bright defects without installing anything.
Full screen
Monitor friendly
Browser based
Black
Default view
Live
Full-screen check
0
Installs
Dark-room friendly
Useful for edge glow and bleed checks that only show clearly on a dark screen.
Quick monitor triage
Helpful right after buying a monitor, laptop, or portable display.
Live display check
Black Screen Test Tool
Start below, switch to full screen, and inspect the entire panel on a clean black background.
Screen Test Preview
Click to Start Full Screen Test
💡 Pro Tip: Clean your screen first! Use arrow keys (← →) or click to cycle through colors in full-screen mode. Press ESC to exit.
Test Statistics
Tests Run
0
Colors Tested
0
What to Look For
- Dead Pixels: Permanent black dots (all colors)
- Stuck Pixels: Dots stuck on one color (red/green/blue)
- Hot Pixels: Always white pixels
- Color Uniformity: Even color across entire screen
Testing Best Practices
- Clean your screen with a microfiber cloth
- Test in a dark or dimly lit room
- View from your normal distance
- Test all 8 colors thoroughly
- Look at edges and corners carefully
- Take your time - don't rush
🔒 Privacy First: This test runs entirely in your browser. No data is collected or sent to any server.
Screen Test Active
Use arrow keys (← →) or click to cycle colors • Press ESC to exit
Black default view
Open directly on a dark inspection screen
Full-screen mode
Check edges and corners without extra UI
Useful in dim rooms
Dark environments reveal bleed and glow more clearly
Local only
The test runs in your browser
Built for dark-screen checks
What a Black Screen Test Helps You Catch
A clean black background is useful when bright defects stand out more clearly than they do on a normal desktop.
IPS glow and haze
Dark screens make glow, haze, and panel flare easier to compare from your normal viewing angle.
Bright defect spots
Hot pixels and stray bright points stand out against a black background.
Return-window inspection
Run a quick screen check before deciding whether to keep a new panel.
Simple workflow
How to Use the Black Screen Test
Darken the room, open the full-screen test, and scan the panel slowly from the center outward.
01
Open the black screen
Start the page and confirm the preview is already on a black background.
02
Go full screen
Use the full-screen mode so the display can be checked without browser chrome around it.
03
Inspect edges and corners
Check for glow, bleed, or bright defects before comparing with white or RGB screens if needed.
Search Intent Cluster
Popular Screen Checks
The same full-screen tester can be used for black-screen, white-screen, dead-pixel, stuck-pixel, and general monitor inspection.
Screen Tester
Run the complete browser-based monitor test with full-screen colors and quick inspection tips.
Open pageWhite Screen Test
Use a full white screen to spot stuck pixels, dust, tint, and uniformity issues.
Open pageDead Pixel Test
Use black, white, and color screens to spot pixels that stay permanently dark.
Open pageStuck Pixel Test
Check for red, green, or blue pixels that stay lit on every screen.
Open pageBacklight Bleed Test
Use a full-screen dark display with adjustable brightness to inspect for backlight bleed, IPS glow, and clouding.
Open pageMore testing tools
Explore the full suite for keyboard, mouse, audio, and utilities.
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Keyboard Tester
Test keyboard functionality, detect ghosting, measure latency, check for stuck keys
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Test polling rate Mouse LOD TesterMeasure your gaming mouse lift-off distance to optimize sensor performance
Test LOD Screen TesterDetect dead, stuck, or hot pixels on screens
Test your screen Monitor Refresh Rate TestDetect if your display runs at 60Hz, 144Hz, 240Hz or higher
Test refresh rate Monitor Color TestCheck color accuracy, gradient banding and backlight uniformity
Test colors Backlight Bleed TestCheck your LCD monitor for backlight bleed, IPS glow, and clouding
Test for bleed Touch Screen TestTest for dead zones, ghost touches and multi-touch on phone or tablet
Test touch screen PWM Flicker TestCheck if your monitor uses PWM backlight dimming that can cause eye strain
Test for flicker Webcam TesterCheck webcam quality, resolution, and snapshots
Test your webcam Mic TesterVerify microphone input and audio levels
Test your microphone Headphone / Speaker TesterTest stereo channels and sound output
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What a Black Screen Test Is Good For
A black screen test gives you a clean dark background for checking monitor defects that are easier to see when the panel should be almost completely dark. It is commonly used for backlight bleed, IPS glow, bright spots, and hot pixels.
If you need the opposite type of check, use the white screen test for stuck pixels, tint, and uniformity inspection on bright backgrounds.
How to Check a Monitor With a Black Screen
- Dim the room so glow and bright defects are easier to notice.
- Open full-screen mode and let your eyes adjust for a few seconds.
- Inspect the center, then the edges and corners for uneven brightness.
- Compare with the dead pixel test or stuck pixel test if you need to confirm the defect type.
Black Screen Test FAQ
Can a black screen show backlight bleed?
Yes. Backlight bleed usually becomes much easier to notice on a dark screen in a dim room, especially around the corners and edges.
Is black or white better for dead pixels?
They help with different things. Black is useful for bright defects and bleed, while white and RGB screens are often better for confirming dead or stuck pixels.
Does this page run full screen?
Yes. Start the display test and switch into full-screen mode for a cleaner inspection surface.
Screen Tester Guide
Quick steps to run the screen tester and review your pixel issues results.
Start the test
- Open the tool and prepare to begin.
- Cycle colors in full screen view.
- Reset to run another quick check.
Adjust settings if needed
- Review tool options for your ideal test.
- Switch inputs or settings if results look off.
- Reset to run another quick check.
Review results
- Look for missed inputs or delays.
- Compare multiple runs for consistency.
- Export or note results if required.
Why is the tool not responding?
Make sure the page is focused and the correct device is selected.
How do I reset the test?
Use the reset button to clear results and start over.
Does this work on mobile devices?
Most tools work best on desktop, but mobile may still function for basic checks.
Can I run multiple tests in a row?
Yes. Reset after each run to compare results.
Is the test private?
Testing runs locally in your browser and is not uploaded.
What should I do if results look wrong?
Try another browser or device to confirm the issue.