Quilt Batting Calculator

About this calculator

The formula adds an overhang allowance on every side of the finished quilt top: batting width = top width + (2 × overhang), batting length = top length + (2 × overhang), with total area = width × length. Quilters typically add 4-8 inches per side so the batting and backing extend past the pieced top, giving enough margin for basting, quilting shrinkage, and squaring up the edges after quilting.

Home quilters use this before cutting into a batting roll or piecing together leftover scraps, so they don't come up short mid-project on a bed-size or lap quilt, while quilt shop owners and longarm quilters use the same math to quote how much batting yardage a customer's top will need.