determine cut length of o-ring

Calculated O-ring Cord Cut Length

( ( OD + ID ) / 2 ) x Pi = length       Pi=3.14159

Use either millimeters or inches for input
Result should be interpreted in your input unit - mm or inch.

Inside Diameter (ID)  =  Outside Diameter (OD)   minus   twice the cross section (C/S)

ID = OD - (2 x C/S)