Height of C9 paper size: 40 mm. = 4 cm.
Width of C10 paper size: : 57 mm. = 5.7 cm.
Dimensions of C9 in mm: 40 x 57 mm.
Dimensions of C9 in cm: 4 x 5.7 cm.
Dimensions of C9 in inches: 1.6″ x 2.2″
Graphic file dimensions in pixels for 300 DPI printing: 472 x 673 px.
Graphic file dimensions in pixels for 72 DPI printing: 113 x 162 px.