CSS vs Physical
Why Browsers Hide True Monitor Size
Privacy standards prevent websites from reading monitor EDID dimensions or OS DPI percentages directly. Online browsers report CSS reference pixels and Device Pixel Ratio.
Display Metrology Telemetry · 100% Local
Screen Size, Resolution & PPI Detector
Read your browser’s live CSS viewport, device pixel ratio, and physical dimensions, then apply your screen diagonal straight into Online Ruler Plus calibration.
Live Browser Signal
Reported Display Properties
- Screen CSS Resolution
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- Estimated Physical Pixels
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- Browser Viewport
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- Device Pixel Ratio (DPR)
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- Aspect Ratio
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- Visual Viewport Scale
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- Active Ruler Calibration
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- Calibration Basis
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Calculated Display Geometry
Physical Dimensions at Selected Diagonal
Select Display Diagonal (Inches)
- Visible Panel Width
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- Visible Panel Height
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- CSS Density (px / inch)
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- Physical Panel Density
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- Physical Pixel Pitch
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Windows & macOS Scaling
Understanding 125%, 150% & Retina Scaling
When Windows scales at 125% or macOS uses Retina “Looks like” resolution, CSS pixel counts shrink while DPR increases—keep browser zoom at 100% when measuring.
Best Verification
Combine Diagonal With Physical Card Check
Even after applying a panel diagonal here, verify against an ISO/IEC 7810 ID-1 bank card in the calibration workspace for sub-millimeter certainty.
Display Scale Reference
Why Effective CSS PPI Governs Physical Size
Compare how identical CSS pixel counts stretch or shrink across uncalibrated monitors and high-DPI laptop screens.
Screen DPI/PPI & Physical Accuracy
FIG. 09 · DISPLAY PHYSICS
Credit Card & Custom Reference Calibration
FIG. 02 · CALIBRATION