Estimating fabric for Sashing, Binding and Borders

When it comes to estimating fabric, I always use the rule it is better to have a little left-over fabric rather than not enough.

I use the width of fabric as 40 inches. The math is always the same.  40 divided by how much you need to cut.  Example 3 ½ square: 40 divided by 3 ½ is 11. Don’t worry about the fractions as they are left over fabric.  You get 11 -3 ½ squares out of a WOF. I know most fabrics are wider but that little bit extra may be needed to use a bias seam (explained later) or errors in cutting. 

Sashing

The amount of fabric needed for sashing depends on the width and the length of the blocks and whether you are using corner stones.  We will use a 20- 12 ½ squares for this example with corner stones

20 – 12 ½ blocks make a quilt 4 feet by 5 feet and you want it bigger.  Sashing will make your quilt bigger.  We will use 2 ½ sashing for this sample.  You will need to count the number of 2 ½ by 12 ½ strips you need.  You have 5 rows down with 4 blocks in each. So across you need 3 pieces for each row.  3 X 5 (rows) = 15.  For the corner stones you will also need 15- 2 ½ inch squares. You will always need the same number of corner stones as pieces across.

For the sashing rows you will need 4 pieces for each row times 4 rows.  4 X 4 = 16 pieces of 2 ½ by 12 ½ strips.  16 + 15 = 31 strips

Cut your WOF at 12 ½ then sub cut into 2 ½ strips.  When you do the math 40 divided by 2 ½  is 16.  Therefor you get 16 strips out of your 12 ½ WOF.  You will need 2 – 12 ½ WOF or 25 inches of fabric to get your needed 31 pieces.  Remember you need 25 useable inches including squaring up fabric. So, I always say 26 inches of fabric to include squaring up and errors in cutting.

Borders and Binding

For borders and binding measure around your quilt and take the total number of inches and divide by 40. The answer you get is the number of strips you need.  If your number is 5.36 you must round the fraction up so you would need 6 strips.  Binding and borders often use bias seams which are sewn on a 45-degree angle.  Two strips with right sides together are placed perpendicular and sewn left to right at a 45 ° angle.    Take the number of strips needed and multiply by the width you require.  6 strips needed at 2 ½ inches wide is 15 inches of fabric.

If you have 29 inches of fabric and need 7 strips for borders take 29 and divide by 7.   You get

4.14 so your border can be cut at 4 inches and viola you have used up all your fabric.

Submitted by Tannis Fahlman

Please click here for a pdf version of this article