As many have already stated, it depends where the kiltmaker places the straps and buckles during construction. Some makers (like myself) place it so that it fits on the middle hole, while others use the tightest hole. Ask if you are unsure.

The kilt straps I currently use have 7 holes spaced 1/2 inch apart. Previously I used 5-hole straps which were also spaced 1/2 inch apart.