Originally Posted by Pat and pups
To add to this question: how do you know how big to cut the fabric to make the tube?
To estimate size of square needed given the length of binding you want: add about 20 extra inches for corners and finishing. You will need a calculator that has a square root symbol. Most calcs have this.
Length of bias X width of strip = area of strip
Square root the number you get for the area of strip
example: 450" long X 2" wide = 900"
enter 900 on calc. and hit the square root symbol you will get the number 30. so a 30" square will give you 450" of 2" wide binding. hope this helps!