In this article from Threads #182 (December 2015/January 2016), Linda Baker describes a method for making pleats where as little fabric is wasted as possible. She writes:

I’ve often found a piece of fabric that would be perfect for a pleated skirt and wanted to make use of the entire length for maximum potential. With the help of my math-whiz spouse, I worked out a formula that tells me what knife-pleat width and spacing I need in order to use every inch of fabric. The formula gives me the numbers, and I make a template to use for marking the pleats on my fabric. For box or inverted pleats, I’ll show you a different formula, but both processes are easy. Grab your calculator and a pencil-you’re just steps away from a party-ready dress or skirt.

Video Web Extra: How to Fold Knife and Box Pleats