I love math. I have always excelled in my math classes growing up, and if I hadn't majored in Accounting, I would have majored in Math. I think quilting goes hand in hand with math.
So today, let's talk about how to figure out yardage.
Figuring yardage on a quilt is important. You don't want to not have enough fabric, and over buying doesn't work for everyone.
You will need to know how many pieces and what size you need and the width of the fabric.
For the example, we will say that we need 300 rectangles that are 3 inches by 2 inches. We will use fabric that is 40 inches wide.
First, figure out how many rectangles will fit across the width of the fabric. Take the width of the fabric and divide it by length of the shape. For the example, that is 40 divided by 3. If this number is a decimal, round down. So the 40/3 is 13.33. Round down to 13.
Next, figure out how many rows of these rectangles are needed. Take the number of the shapes that are needed and divide it by the number you just found. So we need 300 rectangles and 13 can fit in a row, so 300 divided by 13 is 23.07. Round this number up. This would be 24.
Then, figure out how much fabric these rows would be. Take the number of rows and times it by the width of the shape. So 24 rows times by 2 inches is 48 inches.
To convert this into yards, divide the number of inches needed by 36. So 48 divided 36 is 1.333 which is 1 1/3 yards. Feel free to round up to 1 1/2 yards to give a little room for miss-cuts, or twisted fabric.
The formula works for any situation, any shape, inches or cm, just plug the numbers into the appropriate spots.
Have fun quilting (and fabric shopping!)