My biggest was a king size - made of microfiber with fleece as the batting. It was 18" (or 12") can't remember and I made it all on my dinky Brother machine. I stitched in the ditch and it all sounds so simple, but, it was my second quilt and I really didn't know what I was in for with that stretchy microfiber. I also set the blocks on point, so that added to the challenge. It was "fun" dragging it through the machine to quilt. It felt ginormous. I guess it was. Now my son tells me it is "too heavy" and he needs a lighter weight one. Oy. (PS -and it wasn't cheap either. Even with a big JoAnn coupon it cost almost $200)