# Calculating Fold Lines Based on Paper Thicknesses?

I am wanting to know how do you calculate the curvature distance a fold line may produce based on paper thickness?

For instance I am wanting to do artwork on a thick paper stock and I want to make sure my artwork is within the folds instead of perhaps very close to it. As what I am doing is on small thick boxes, it is critical that I can work this out.

Many thanks.

Length of a perfect circular fold for 180 degree turn is π × W:

Image 1 Corner shift

In practice thus you have some slack to the inner side, so W is actually width of paper plus how much inner radius you use. So W is somewhere between 1-2 times the width of the card stock. and the amount of paper that the corner eats is:

π × 1-2 × w × a/180

where a is the angle of your corner, and w is the width of your cardstock. A value 2 might be pushing it i have never needed to measure card stock this accurately so i allays used a value of 1, but i do regularly accurate sheet metal work which is similar tech. So this is the theoretical underpinning.