Calibrate
hold a bank card to the screen. any bank. drag the knob until the outline matches.
your card here
85.60 mm × 53.98 mm
reading: —
That's my card
skip — trust the guess
0.00 cm
0.00 in
Ruler
drag anywhere to measure point to point. drag the ruler to move it.
Recalibrate
display:
devicePixelRatio:
your screen: