Many predesigned quilt patterns provide instructions to help you buy the right amount of the different fabrics you need to make the quilt. If you’re designing your own quilt, you’ll have to calculate the yardage you need. To calculate fabric yardage for a quilt:
- Count how many of each piece you need.
- Determine the dimensions of each piece, including seam allowances.
- Calculate the yardage for each fabric you’re using.
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Count How Many of Each Piece You Need
To figure out the total yardage you need of each fabric, you have to determine how many pieces of each fabric your design requires. For instance, for the sample 60″× 60″ quilt shown in Quilt Design Basics, you would need:
- Light blue squares: 39
- Dark blue squares: 26
- Yellow squares: 12
- White squares: 148
It’s easier to count the number of pieces you need if your quilt pattern contains blocks of repeating patterns. For instance, the sample design has 13 blocks, each of which contains 3 light blue squares, so you can then do the multiplication to get 39 light blue squares. That approach is easier than counting up all 39 squares, one by one.
Determine the Dimensions of Each Piece
The dimensions of each piece depend on your design and the size of the quilt. For instance, the sample 60″× 60″ quilt has 5 blocks across and 5 blocks down, meaning that each block is 12″× 12″. Each block has 3 squares across and 3 down, meaning that every square must be 4″× 4″.
Factor in Seam Allowances
Though each square piece will take up 4″× 4″ of the finished quilt, each square itself will be larger than 4″× 4″ because of the seam allowances. Since quilting seam allowances are 1/4″ on all sides, any piece must be 1/2″ larger in both width and height. Thus, each square’s actual measurements have to be 4 1/2″× 4 1/2″.
Calculate Yardage for Each Fabric
Quilting fabric comes in a standard width of 44″, but each side has a 1″ selvage edge, which consists of densely woven threads designed to keep the fabric from fraying. You should trim off the selvage before quilting, reducing the fabric’s width to 42″. So when you buy a yard of fabric, you’re actually buying fabric that’s 42″ wide by 36″ long. To figure out how many yards of each type of fabric you need:
- Determine how many squares of a particular piece can fit into the 42″ width of the fabric: Divide 42″ by the width of the pieces made of that fabric. For the sample design, you’d do: 42 ÷ 4 1/2 = 9 1/3. Since you can’t work with 0.33 of a square, always round this number down. You now know that you can fit 9 squares that are each 4 1/2″ wide across the 42″-wide fabric.
- Determine how many rows of squares you need to get your total amount: Divide the total number of pieces you need in that fabric by the number of pieces that fit in a row. For instance, to figure out how many rows of 9 light blue squares you need to get 39 total squares, you’d do: 39 ÷ 9 = 4 1/3. To make sure you get enough fabric, always round this number up. In this case, you’d need 5 rows of squares.
- Determine how many inches of fabric you need: Multiply the number of rows you need by the length of the pieces. For the sample design, you’d do: 5″ × 4 1/2″ = 22 1/2″.
- Determine the yardage: Convert the inches to yards by dividing by 36″ (1 yard). In this case, you’d do: 22 1/2 ÷ 36 = 5/8 yards. Since it’s best to overestimate the amount of fabric you need in case you make errors, round up that number to 1/3 or even 1 yard.
For the sample design, you can use the same process to find out the yardage of yellow, dark blue, light blue, and white fabric.
Calculate Yardage for the Quilt Backing
The backing of your quilt should measure 2–4″ longer and wider than the quilt top to account for shrinkage that occurs during quilting. Though you can piece together a backing from regular quilting fabric, it’s easier and less costly to use muslin. This inexpensive cotton fabric comes in widths up to 120″ and is more comfortable to sleep under than regular quilting fabric. Muslin’s only downside is that it’s typically available only in white.
Calculate Yardage for Borders and Sashing
If you’re making a quilt with a border or sashing, you need to calculate yardage for those pieces as well.
- Border: The width of a quilt border is up to you. The length of the border should be equal to the length of the side it’s bordering, plus 4″ to allow you to connect the borders in each corner with mitered edges.
- Sashing: Count the number of squares and rectangles of sashing you’ll need, calculate their dimensions (including seam allowances), and use the method for calculating yardage for quilt pieces.
Estimate Fabric
If you don’t want to do all the math, you can estimate how much fabric you need by following these steps:
- Estimate the percentage of a quilt top made up of a certain piece: For the yellow squares in the sample, you might estimate that they take up 5% of the surface.
- Multiply the percentage by the measurement of the backing: For the sample design, you would figure out that you need 5% of 4 yards of fabric, which is the same as 0.2 yards. Just to be safe, you might want to increase that to 0.25 yards of yellow fabric.
