Quote Originally Posted by psyopper View Post
What does this mean?
It means make it bigger than the actual measurement. There are two sorts of ease commonly added (or in some cases, taken out) of clothing. There's wearing ease, which is extra fabric that's added to make wearing the garment comfortable (or even possible, in some cases.). Measure the waist of a pair of pants; you'll find that they're an inch or two larger than the size on the tag. In the case of things that are supposed to be skin tight and are made of stretch fabric (wetsuits, some women's sweaters) wearing ease can be zero or even negative. Design ease is ease added by the garment designer, to make the garment looser, or removed to make it more fitted.

I expect that your kilt's hip line has the exterior measurement that you want for the interior. Remember that the outside is longer than the inside. There are quite a few layers of fabric in even an X kilt, so the inside can be a bit smaller than you thought it was going to be.