Quilters will often come into the store asking for help to calculate yardage for a quilt back. We love to help but that is often a loaded question. It depends on how you intend to construct or piece your back. There are multiple ways to do this and none are more right or wrong than the other.
It is important to note in all cases that you should measure the center length and center width of your quilt top to determine the actual length and width.
Sometimes you want to piece the back with lengthwise seams. In this case you would buy the yardage the length of your quilt. You may have to double or triple the yardage if the quilt is wider than 40 inches or 80 inches.
Other times it is more efficient to piece the back crosswise. In this case you would buy the yardage the width of your quilt and double or triple the measurement if the length is longer than 40 or 80 inches.
I’ve become a big fan of piecing my backs from scraps. I get two quilts in one this way. So I would determine yardage based on the quilt pattern. I always design the border to accommodate the fact it’s going to be lopped off after quilting.
You can get similiar dual purpose out of your backs using cheater fabrics and crosswise and lengthwise seams. Some great “cheater” fabrics at Wish right now are Winter Log Cabin (in the sale room!), and In Love With Nature’s Pinwheels by Susan Branch. I used the Winter Log cabin on the back of Cheery Cherry Pie, the Sew Sweet Shop Scrap club sample quilt hanging in the front of the store.
Another, less known way, of piecing a back is John Flynn’s biased seam method. It’s a very smart technique. If you are going to put your quilt on a frame this is the best way to distribute the back seam. It’s also the most effiecent use of yardage. John has posted his method on his website. If memory serves me correctly he has a great demonstration on how to fold and cut that long bias edge with your 6 inch by 24 inch ruler on his instruction video that he packs with his frame. The basic formula is:
Length of fabric to buy = length of quilt top + length of quilt top( width of quilt top – width of fabric)/ 2 x width of fabric – width of quilt top
For those who get confused by equations:
Record the width and length of your quilt top (add any desired overhanging for the back to these measurements before you begin any other calculations). Record the width of the fabric you are considering (usually 40-44 inches. I’d recommend using 40 if you are unsure).
Multiply 2 times the width of the fabric you are considering (if you are using the safe bet of 40 then this will always be 80 inches). Subtract the recorded width of the quilt top. Save this first number.
Take the recorded width of the quilt and subtract the width of the fabric being considered (40). Multiply by the recorded length of the quilt. Add the recorded length of the quilt. Now divide by the first saved number.
Voila! You have the recomended length of fabric in inches. Divide by 36 if you want yards.
Or you can just come into Wish and we’ll put two heads on the calculations and help you out.
Do you have another method of calculating yardage for a quilt back?