batting has to be larger than your quilt top to make up for the shrinkage that commonly occurs when you quilt your quilt, and gives you some lee-way if your quilt is not perfectly squared up. the basic measurements are of the top of the mattress, does not include a pillow tuck or overhang. if you want your quilts to fit your bed measure your bed, add the amount you would like for an overhang, and pillow tuck then adjust your patterns to fit your needs.