Every standard credit card, debit card, driver's license, and gift card is manufactured to the exact ISO/IEC 7810 ID-1 standard (85.60 mm ร 53.98 mm / 3.370 in ร 2.125 in). Use yours to calibrate this ruler to 100% true physical size.
Browsers don't expose a monitor's real size, so ticks default to a 96 DPI guess. Hold a physical object against the screen and drag the slider until the box below matches it exactly โ the ruler will then be accurate to your display.
Match your operating system's visual scaling with real-world physical dimensions.
All standard bank credit cards and ID cards measure exactly 85.60 mm wide by 53.98 mm high (3.370 ร 2.125 inches).