Welcome from St. Louis.
It seems that however hard you try, one part, either the top or the bottom will shift, or be just a tad smaller. So plan ahead and make the back larger to give you some wiggle room! It will help when you position the batting and top on the backing.
If you have your backing pieced, just add another border and go with it.

Welcome from Arkansas!

Welcome neighbor! This site is great!

Hello and welcome from Germany. I guess, the 4 " are required for having it quilted by a longarm. For myself and my domestic machine I dare to make it smaller, like 1" or 2 " larger than the top.

Howdy from Kentucky!! http://www.freesmileys.org/smileys/s...um/welcome.gif

Good Morning from michigan! the extra 4 inches all the way around, if for sending your quilt to a long armer..they use the extra to clap,pull or tighten it on the frame.

you only need a few inches it your doing it yourself..

welcome from Michigan.

Hello and welcome from central Alabama.

Welcome from NE Indiana :thumbup:

Welcome from SW Missouri. There's a lot of wonderful information on this board.