Kilt waist size?

[The Wizard of BC]

As you can see from the responses so far the thinking on this is all over the place.

The truth is that there is no one, or right, or accepted, way to measure or describe a size.

To compound the problem you specified a modern kilt. These can be whatever. I've seen some modern kilts listed based on their relation to jeans size. i.e. "This will fit someone who wears size 34 jeans."

It is well known that jeans size has nothing to do with what a tape measure would read. I know guys who wear size 34 jeans yet weigh in at better than 250 pounds.

So, no, never assume that the size listed is the size you think you are. Don't even try to guess. Trying the kilt on is the only sure way to know.