Fortunately the calculations are quite simple.
The first step is to determine the perimeter or outside edge of your quilt.
- Take a measurement across the quilt widthways. It doesn’t matter where you take this measurement it can be at the end of the quilt or across the middle.
- Take a measurement the length of the quilt, again it doesn’t matter where you take it from, either down the side or the middle of the quilt.
In my example the short sides were 14″ and the long sides were 33″.
Multiply each measurement by 2 as you have 2 short sides and two long sides.
14 x 2 = 28, 33 x 2 = 66.
Add 28 and 66 together and you get a perimeter measurement of 94″.
Now add 10″ to allow for cutting off selvedges and sewing the strips together, making the perimeter of you quilt 104″.
The next step is to determine how many strips of fabric you need to cut.
Measure your width of fabric (WOF). Usually this will be 42″ -44″. I use 40″ in my calculation so that I have some excess fabric to work with.
Take the measurement of the perimeter and divide it by the measurement of the WOF, remember that I always use 40″. (perimeter) ÷ (WOF). So 104″ ÷ 40″ = 2.6.
Now we aren’t going to cut 2.6 strips, we will just round it up to 3 strips.
This means that we need 3 strips to bind our quilt.
See how easy it all is. This formula works for any sized quilt.
Just supposing you don’t have fabric on hand to make your binding then the next thing you will want to know is how much fabric to buy. And that is another simple calculation.
How to determine how much fabric to purchase
Firstly determine how wide your binding is going to be. I make mine 2½” wide.
So you need to know the number of strips that you require. We worked that out in the last step. and we need to multiply that by the width of the strips.
I worked out that I needed 3 strips at 2.5″ wide so I multiply 3 x 2.5 and that gives me 7.5″
So I will need to buy ¼ of a yard to make my binding.