How to calculate quilt borders
My quilt measures 56x61 inches and the fabric I want to use as a border measures 44x37 inches.
How wide do I make the border strips?
And how do I figure this?
All of the borders will need to be pieced because your border fabric is shorter than either the length or width of your quilt top.
The calculations are based of these assumptions:
- The usable width of fabric (WOF) is 42" (44" minus the selvedges and 1" for seam allowances). If your width varies from this assumption, plug in the new WOF in the math below.
- You have 37 usable inches of a 44" wide fabric. The strips will be cut on the crosswise grain (from selvedge to selvedge).
- Binding will be cut from a contrasting or coordinating fabric.
- Long horizontal border strips are used as shown in the image at the top of this page.
The CalculationsStep 1: Determine how many inches of continuous border strip is needed
Add up the lengths of all the sides
56 + 61 + 56 + 61
Don't forget to add the lengths needed for the corners, so add the unknown length in now to get
234 inches plus 4 times the width of the border strip
This might look a bit complicated because we're working with an 'unknown' number, but it's just math. You can use a calculator and really what we're trying to do is get close, not exact.Step 2: Try a strip width
Let's start with a strip width of 5". From a length of 37" you can cut seven 5" strips with 2 inches left over for your scrap basket.
37" divided by 5" Step 3: Calculate how many continuous inches of border strip this makes
7 full strips
7 strips times 42" of usable WOFStep 4: Evaluate
Use this information to evaluate our equation from Step 1 above.
234" plus (4 x width of the border strip)
234" + (4 x 5")
234" + 20"
254" of a continuous border strip needed
Compare this to 294" or the amount of continous border strip created from 7 strips.
The 294" of continuous strip created is greater than 254" needed. You have enough yardage if you cut 7 strips 5 inches wide from your border fabric.
Can you cut your strips 5-1/2" wide and have enough?
Just run through the calculations again substituting 5-1/2" for 5".
With a 5-1/2" border the continous border strip needs to be 256 inches (234" + (4 x 5-1/2").
Six 5-1/2" strips can be cut from the border fabric (37" divided by 5-1/2" rounded down to the nearest whole number)
Which makes a 252" continous border strip (6 times 42" usable WOF), clearly not enough for 256 inch piece needed.
I can't stress this enough...
Be sure that the fabric you'll cut the strips from is square. If it was cut wonky from the bolt you may not have the full, usable 37" width. Without that, you might not be able to cut the necessary number of strips.
And as always, double check the math. It's so easy to make a simple mistake. Easier to correct the numbers, then cut the fabric wrong and have to find a new border fabric.
Thank you for your question.