Many quilters are great toppers, but when it comes to making the backing for their quilt, they can get stumped pretty easily. Calculating the fabric that you’ll require for your quilt back is not rocket science, but you do need to have the knowhow, to get that backing measurement and making it spot on.
Firstly, let’s assume that you’re going to be working with fabrics that are the standard 42” – 44” wide. You will need a calculator from here on in.
Here’s the theory:
Multiply the length by the width of your quilt.
Divide this answer by 1296 (which is the number of inches in a square yard).
Your answer will be the amount of yards you will need to cover your quilt.
At this point you will add another half a yard which is required for the 4-5” overhang your need around your quilt top.
So, let’s put it to the test.
Say your quilt top measures 72” x 90”.
Multiply 72 x 90 = 6480
Divide 6480 by 1296 = 5
Add another half yard for overhang = you will need to purchase 5 ˝ yards for your 72” x 90” quilt top.
Ok so we know it’s never a good idea to have a backing fabric seam running down the centre of your quilt – it actually weakens the quilt backing. It’s always best to divide the back of the quilt into thirds and then place the seams there.
Just a note here: remove the selvidges from the edges of the fabric. This will give you approximately 42” of fabric width to use.
For the seams to run vertically, cut two 42” x 94” (90” length plus 2” extension at top and bottom of quilt top) lengths of fabric. Take one of these and recut it into two 21” x 94” lengths. Sew one of these to each side of the 42” x 94” piece.
You will now have a strong backing fabric piece for your quilt that will have approximately3” extension on all sides, ready for domestic machine quilting. If you’re having your quilt professionally quilted with a long arm quilter, remember to have an overhang of backing fabric approximately 4” bigger than the quilt top.