Quilt Backing Calculator

Use this handy quilt backing calculator to calculate the backing yardage for your quilt and the required number of seams.

Quilt Width *Enter quilt width in inches

Quilt Length *Enter quilt length in inches

Width of Fabric (WOF) *Enter width of fabric

Overage *Enter desired overage (on each side) in inches

This free online quilting calculator is a basic version of the powerful quilting calculator available in our quilting calculator app – Quilt Geek. It’s designed to give you quick and easy fabric measurements, but for more advanced features and customization, check out our full app!

How to Use the Quilt Backing Calculator?

Wondering how much backing fabric you need? This quilt backing fabric calculator will calculate the exact backing fabric yardage needed for your quilt. It takes into account the width of the fabric you are using and the desired overage, so you will always get exact fabric requirements.

Begin by entering the quilt top width and quilt top length. Use the illustration as a guide. The QW (quilt top width) is the horizontal dimension of the quilt top and the QL (quilt top length) is the vertical dimension of the quilt.

Enter the width of the fabric (WOF) you are using. This is the width of the fabric, measured from one selvage edge to the other. If you don’t enter any number, the calculator will use the default, which is 42’’ (as this is the most common WOF for quilting cotton). 

Enter the desired overage. This is the amount of fabric that hangs over the edge. It is necessary for long-arm quilting to attach the quilt to the frame, so consult your long-armer about the required overage. Even if you plan to quilt on your domestic machine or by hand, some overage is required to account for the shifting of the quilt sandwich layers as you quilt.

Press CALCULATE to run the calculation.

Reading the Results of the Backing Fabric Calculator

The calculator provides two different calculations:

Option A calculates the backing fabric yardage (in inches and yards) for vertical piecing.

Option B calculates the backing fabric yardage (in inches and yards) for horizontal piecing.

The value in yards is rounded up to the nearest 1/8 of a yard.

For each, the number of backing fabric pieces and the number of required piecing seams are calculated. If more than one fabric piece is required, the calculator adds the seam allowance required for piecing (a 1/2” seam allowance is added) to the final yardage calculation.

Vertical or Horizontal Seam on Quilt Backing

When deciding whether to use vertical or horizontal seam(s) on your quilt backing it usually comes down to using as little fabric yardage as possible. If the direction of the fabric you are using as your backing is irrelevant, choose the orientation that uses the least yardage.

If you want the print to run in a specific direction, choose the fabric placement accordingly. The illustrations below show the backing fabric direction depending on the chosen fabric placement.

Vertical Backing Fabric Placement

If using vertical backing fabric placement, the backing fabric selvage runs vertically (parallel to the length of the quilt). If seams are required, they run vertically.

Horizontal Backing Fabric Placement

If using vertical backing fabric placement, the backing fabric selvage runs horizontally (parallel to the width of the quilt). If seams are required, they run horizontally.

Quilt Backing Chart

In case you prefer a chart as a quick reference, you can download our free quilt backing chart!

The quilt backing chart includes the backing yardage for some typical quilt sizes assuming the width of fabric (WOF) is 42”.

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!