Real-size ruler

Screens differ in pixel density, so calibrate once: hold any standard bank or ID card (ISO/IEC 7810 ID-1, 85.60 × 53.98 mm) against the screen and adjust until the outline matches its edges.

1 · Calibrate

Browser zoom changes the result: keep zoom at 100% and recalibrate after changing it. Calibration is stored only in this browser.

2 · Ruler

3 · Device at real size

Pick a device