How to Piece a Quilt Backing + Quilt Backing Chart

Learn how to piece a quilt backing no matter what size your quilt is. We’ve included a handy quilt backing chart to help you plan your backing easily.

You’ve pieced your quilt top and you’re super proud of it. Yaay, I’m genuinely happy for you. But as you know, your work here is not done. You’ve still got some sewing to do before you can snuggle under that quilt.

One of the next steps will be to make a quilt sandwich and baste your quilt. But you can’t make the sandwich without first preparing your backing.

If you’re still wondering what fabric to use for your backing, go read our Best Quilt Backing Fabric guide first. And then come back, so we can do some quilt math.

Calculating Quilt Backing

I know calculating the quilt backing can get a bit overwhelming. When all you really want to know is how much fabric you need for a king size quilt backing. Or queen size. Or baby. Or whatever size your lovely quilt top is.

Well, friend, you’ll be happy to hear that I’m about to explain every single step right now. Two ways. The old-school way, which includes some a lot of calculus on your part, and the easy modern way with our online backing calculator.

I should probably mention at this point that some manufacturers offer wider backing fabrics (up to 108’’ wide) which make the calculating process a bit easier. However they are offered in a limited selection of patterns and colors, so it might be worth doing the calculations so you can use whichever fabric you like best.

Quilt Backing Chart

Before I go into all the details of how to calculate and piece the quilt backing, here is your chance to get our free Quilt Backing Chart for reference.

The quilt backing chart includes the backing yardage for some typical quilt sizes assuming the width of fabric (WOF) is 42”. If you’re making a different size quilt, or using a fabric with a different WOF, use our backing calculator!

So how do you get this chart? Easy! Just sign up for our newsletter and we’ll send you the chart as a welcome gift!

How Much Fabric Do I Need For A Quilt Backing?

Due to the large sizes of quilt tops, you will most likely have to assemble the backing using multiple pieces of fabric. When trying to calculate the yardage for your quilt back, there are different things to consider. First, you’ll need to decide on how you’re going to piece your backing. The two options are: horizontal and vertical backing seams.

(We’re going to look at how to piece one single fabric where the WOF (width of fabric) is 42″. That doesn’t mean you can’t use different fabrics and piece them together or even make a scrappy quilt backing. But we’ll save these ideas for some other time.)

Horizontal vs. Vertical Backing Seams

As I’ve said, you can assemble backing fabric using horizontal or vertical seams. When deciding between the two, it comes down to the following: 

1. Saving On Fabric

Depending on the size of the quilt, using one type of seam will use up more fabric than the other. If you’re using non-directional fabric, this will be your main deciding point. 

Generally speaking, when using 42″-wide fabric, you will use less fabric by doing:

• Horizontal seams if quilt top width is up to 60″
• Vertical seams if quilt top width is more than 60″

2. Using Directional Fabric

When using directional fabric (a fabric where there’s a clear up or down to the pattern) you will probably want the print to go a certain way. In this case, the seam orientation depends on the direction of the pattern on the fabric.

How Much Bigger Should The Quilt Backing Be?

The backing for your quilt has to be larger than the actual quilt top. 

If you’re sending your quilt out to a longarmer for quilting they need the extra fabric (also called overage) to properly set it up for quilting. And if you’re planning to quilt it at home, you’ll also need that extra fabric that is taken up during quilting. 

Add an extra 4″ of fabric all around (that means an additional 8’’ to both the width and length measurement of the quilt top). 

To be completely honest, I have gotten away with an inch on each side when machine quilting in the past, but I don’t recommend it. Do as I say, not as I do, right? 🙂

Now that the basics are clear, let me explain how to actually calculate the amount of fabric you will need for your quilt backing.

How to Calculate Yardage for Quilt Backing

Method 1: Do The Math Yourself

If you’re a quilt geek, you might want to do this thing old-school style. That means you and your good old calculator and some math. I also call this the hard way, because we really do have a much easier way for you. But I’ll try to explain this nevertheless because I think it may help with understanding how quilt backing is calculated.

Step 1: Measure the Quilt Top

The size of the quilt backing must, obviously, correspond to the size of your finished quilt top. So, how do you measure for quilt backing? First, make sure your quilt top is squared. Then lay it out on a flat surface and measure the width and length of the quilt top.

Step 2: Add 8” Overage to get the Required Backing Size

As I’ve explained earlier, the quilt backing should be about 4″ longer on each side of the quilt top. This means you need to add 8” to both the width and the length of the quilt top to get the required backing size.

Step 3: Determine the Piecing Configuration

As I’ve explained earlier (if you skipped it, scroll up to get the info), you will need to determine the orientation of the seams on your backing. Use the guide above to decide whether you will use vertical or horizontal seams.

Step 4: Calculate the Yardage to Purchase

This calculation assumes WOF is 42″ and overage is 4″ on each side.

QT = quilt top 

If no seams are needed (for very small quilts – quilt top width is up to 34″):

Backing (in inches) = QT length + 8″ 

Divide by 36 to convert to yards.

If Using 1 Horizontal Seam (usually when quilt top width is 34″–60“):

Backing (in inches) = (QT width + 8“) x 2 

Divide by 36 to convert to yards.

If Using 1 Vertical Seam (usually when quilt top width is 61“-74“):

Backing (in inches) = (QT length + 8”) x 2 

Divide by 36 to convert to yards.

If Using 2 Vertical Seams (usually when quilt top width is 75“-116″):

Backing (in inches) = (QT length + 8”) x 3 

Divide by 36 to convert to yards.

Method 2: Use Our Quilt Backing Calculator

As I promised, there is an easier way to do this. It is by using our Quilt Backing Calculator.

It is so easy to use! Enter the width of the backing fabric (WOF), the size of your quilt top, and the overage you want for your backing. Click ‘Calculate’ and let the calculator do the work for you!

The calculator provides two results: one for vertical piecing and the other for horizontal piecing.

It tells you exactly how much fabric you’ll need AND how many seams are required to make your backing. It doesn’t get much easier than that! Click here to calculate!

How To Piece A Quilt Backing

Now that the hard math part is behind us, it is time to actually piece the backing pieces together. This is not hard at all, but it might be useful to have a step-by-step guide, so here it is:

STEP 1

Remove the selvages (the tightly woven edges) from your fabric.

STEP 2

Cut the fabric to the required backing size.

For vertical seams, cut WOF x required backing length

For horizontal seams, cut WOF x required backing width

Depending on your calculation, you will need to cut 1 to 3 pieces (or even more if you’re making something very big).

STEP 3

Lay two pieces right sides together. Pin them to keep them in place. 

STEP 4

Sew with a ½” seam allowance (this larger seam allowance makes for a more durable seam).

STEP 5

Press the seams open.

STEP 6

If piecing together more than 2 pieces, repeat steps 3-5 to sew all the required pieces.

STEP 7

Because you are working with WOF pieces, chances are, the pieced backing will be too large (too wide or too long). Cut away any extra fabric to get the required size of the quilt backing.

And that’s pretty much it! You’ve just learned how to piece a quilt backing and calculate backing fabric yardage.
Are there any other tips or tricks you use when planning your quilt backing? I would love to know!

P.S.: If you want to try some more creative ideas for piecing your backing, we have a great blog post with 20+ creative pieced quilt backing ideas!

Backing Yardage for Standard Quilt Sizes