How to use it
Enter the requested values and review both the result and the assumptions shown on the page.
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On-Screen Ruler
Calibrate your display with a bank card, then measure horizontal and vertical lengths in cm, inches or pixels.
100% browser zoom recommended
Device scale: 1.00×
Distance between guides
Drag the pink guides to measure a length.
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Actual-size calibration
Match the rectangle below to the width of a physical bank card.
Physical screen size varies by device. Calibrate with a card first for accurate measurements.
Standard card 85.60 mmCARD
TOOL GUIDE
When to use it
Content reviewed · 2026-07-24
Calibrate your display with a bank card, then measure horizontal and vertical lengths in cm, inches or pixels.
Before you rely on the result
Results can vary with the browser, operating system, display, and input device.
Data handling
Inputs and files are processed in this browser and are not uploaded for the task.
Related tools
A few tools that fit naturally with this task.