how do you calculate cross sectional area
To calculate the cross sectional area (CSA) of a cable, you have to use a micrometer to verify its diameter, then divide the diameter by two to get the radius (r).With the ra â¦ dius we can calculate the CSA of the cable.    CSA = pi x r2 (Applicable to solid wires only).se the formula pi x r2 (3.14 x radius x radius) to get the cross sectional area. The formula works for all measurement units whether they are inches, millimeters, centimeters or others. An alternative is to use (pi x d^2)/4. (3.14x diameter x diameter divided by 4) You do not then need to divide the original diameter.