Originally Posted by
brushandthimble
Ditto. I always use the 40 inches in any math I am doing.
You are safe with this assumption - unless you are using much older fabrics than
42 inch wide fabrics are not 'new' - and, interestingly enough, some of the pricier brands are narrower than the VIP ones were.
I haven't bought much 'new' fabric for about five years, so can't comment with certainty about that - but I am very certain for 5-20 years ago.