The size of the kilt (4 or 8 yard... or 6 or 11 or whatever lenth needed) depends on 3 things:

1 Width of each pleat. The smaller the pleat, the more pleats are needed to cover the same area.

2 The size of the repeat. I find that most of the tartans we deal with have a 7 inch repeat (give or take an inch). However, some have a 4 inch repeat and some have a 11 inch repeat. The biger the repeat pattern chosen by the kilt maker (they can use every repeat or every OTHER repeat), the more material needed.

3 The WAIST / HIPS of the wearer! This one is often overelooked. If there's a guy with a 34" waist and his friend with a 54" waist wants the SAME style kilt with the SAME pleat depth and SAME pleat width, then the guy with the 54" waist WILL GET a kilt with more yardage. This is the reason that there's often a "tax" for bigger sizes. They take more material (this stuff ain't cheap) and they take longer to make.

Be wary when someone says that they make an "8 yard kilt". It probably isn't exactly 8 yards. That's not to say it isn't a good quality kilt, just the use of the term "8 yards" may be a bit misleading. I find that I make many 6 yard 7 yard or 9 yard kilts... so I never tell people before hand how many yards go into it. If they want to know after I'm done "doing the math" to figure out how much yardage to use, I'll gladly tell them.

Footnote: This post isn't meant to "slam" any kiltmakers... just reasons for why we (Kelly and I) do things the way we do.