How to calculate the fabric needed for a quilt binding

This is a useful post to help you calculate how much fabric you need for any given binding. I’m going to list all the steps below. For these examples, I am working in inches, but you can follow the steps and go through exactly the same process in centimetres if you prefer to work in metric.

Three ways to cut a binding

First of all, I need to point out that there are three ways of cutting a quilt binding. If you are binding a quilt with curved edges, you will want to cut your fabric on the bias (corner to corner), as shown in the third diagram below to make use of the stretch. If you need a really sturdy binding, you might choose to cut binding strips running down the length of the fabric, parallel with the selvedge, as shown in the second diagram below. The reason for this is that the warp threads (up and down) are stronger than the weft threads (side to side). However, unless you have a special reason to do otherwise, most of us cut binding fabric across the width of the fabric, as shown in the diagram immediately below.

A double binding cut across the width of the fabric

This is how to calculate how much fabric you need to buy.

Step 1 is to measure your quilt. Let’s say your quilt is 48″ wide and 60″ long.

Step 2 is to add all the sides together. So the sum is 48 + 60 + 48 + 60 = 216″

Step 3 is to include an extra 10″. This allows for the seam allowances when joining the binding strips – I join mine end to end with a straight seam. It also allows some extra length when it comes to joining the two ends of your binding, when you finish. So the sum is now 216″ + 10″ = 226″

Step 4 is to measure the width of the fabric you are using for your binding. Let’s say it is 42″

Step 5 is to work out how many strips across the fabric you need. This is 226″ (your total binding length) divided by 42″ (the width of your fabric). So the sum is 226  ÷ 42 = 5.38

Step 6 is to round this up to a whole number, so in this case the number is 6

Step 7 is to decide how wide you want your binding to be. I recommend using a double binding, in which the strip is folded once down the middle before being attached, as this makes for a more robust binding. Let’s say you decide to cut your binding at 2½”.

Step 8 is to multiply the number of strips you need (6) by the width of strip you have decided on (2½”). So the sum is 6 x 2½” = 15″

You can change any of the variables in this steps and still get the right answer, for example: the width of the fabric, the width of the binding or changing it all into metric, the method will still work.

Hope you find this useful!

For a tutorial on how to add a binding to a quilt go here

Sewing on a quilt binding

Next week’s blog post will be the July block for the mystery quilt ‘Watch the Stars’.

Watch-the-Stars Mystery Quilt 2022 with Amanda Jane Textiles, white lettering on a dark blue background, four yellow on blue star blocks at the bottom

Amanda Jane Textiles offers unique fabrics for sale here, quilt patterns here, classes here and quilts for sale here

Here’s a fabric design for a summer’s day: ‘Ice Cream, Please’. Buy it here

Published by Amanda Jane Textiles

I am an artist, designer and maker living in Ramsgate, UK

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