Monitor Contrast Test
Use black, white, window, and checker patterns to inspect shadow detail, highlight clipping, and perceived contrast.
Contrast and pattern settings
Visual mode is for observation; readings mode records values you already measured with a separate instrument.
Optional readings
Enter a luminance reading only if you have measured it separately.
The value is optional and does not turn a visual check into an instrument measurement.
Use a floor only to classify an entered black reading.
Contrast preview
Look for detail near black without confusing room reflections with panel output.
Look for detail near white in the white window and step patterns.
- White level
- Not entered
- Black level
- Not entered
- Pattern
- Step pattern
- Window
- 25%
- Local dimming
- Unknown
- Environment
- Dim room
- Shadow detail
- Not checked
- Highlight detail
- Not checked
- Ready
- 0/4
Contrast observations are sensitive to room light, viewing angle, panel behavior, and the chosen window size.
Interpret the result
Use the same pattern and setup when comparing displays. A visual observation should be repeatable before you treat it as an issue.
More information
How to use the test
Keep the comparison consistent
Set a stable viewing position and use the same room lighting. Start with the checkerboard, then inspect black and white windows.
If you enter readings, label them as readings from another instrument; the page does not measure luminance itself.
Method
Patterns and optional readings
The page renders controlled black, white, step, and checker patterns with selectable window sizes.
Visual mode stores observations; meter mode records values you provide and checks their basic relationship.
Boundaries
What this cannot prove
The test cannot establish a certified contrast ratio, HDR performance, or laboratory black level.
Ambient light, local dimming, display profile, and browser rendering can change the visible result.
Frequently asked questions
How do I check monitor black level?
Use the black pattern in a stable room, keep the display at its normal viewing angle, and compare shadow detail around the selected window. Record a visual observation rather than a numeric claim.
Why can shadow detail look different with local dimming?
Local dimming changes backlight zones according to the pattern and window size, so black level and nearby shadow visibility can vary with the test pattern.
Does this measure contrast ratio?
No. It offers visual patterns and can record readings from another instrument, but it does not measure luminance itself.
Why does room lighting matter?
Reflections and eye adaptation change the appearance of near-black and near-white details, so a stable environment is important.
Privacy, method, and sources
Settings, timers, and observations stay in this browser. Nothing is uploaded, and no remote API is called.
Source notes
Patterns use browser rendering and the Fullscreen API; numeric readings are optional user-provided values.
The page uses independent tool code without third-party runtime services.