How Much Binding Do I Need for a Quilt?

Binding is the narrow strip that wraps the raw edges of a finished quilt. Running short means a trip back to the shop and, worse, a fabric that may no longer be in stock. The arithmetic is simple once you see it laid out.

Step 1: measure the perimeter

Measure the quilt top through the middle in both directions, not along the edges, which can stretch. Add the width and length together and double the result. That is the perimeter: the total distance your binding has to travel.

Step 2: add an allowance for joins and corners

Binding strips are joined end to end, usually with diagonal seams, and each join uses up a little length. You also need a tail at the start and the end to join the binding neatly, and some extra to fold the mitred corners. Our calculator adds 10 inches to the perimeter for all of this. If you like long tails, add a few more inches yourself.

Step 3: count the strips

Strips are normally cut across the width of fabric, selvage to selvage. Quilting cotton is sold at 42 to 44 inches wide, but after you trim the selvages and square up, about 42 inches is usable. Divide the binding length by 42 and round up to a whole strip: you cannot cut part of a strip.

Step 4: work out the fabric

Multiply the number of strips by the strip width you cut. That gives the length of fabric in inches. Divide by 36 to get yards, then round up to the next 1/8 yard, which is the smallest cut most shops will sell.

Worked example: a 60 x 72 inch throw

Perimeter: 2 x (60 + 72) = 264 inches.
Add 10 inches: 274 inches of binding.
Strips: 274 / 42 = 6.52, so cut 7 strips.
Fabric at 2 1/2 inch strips: 7 x 2.5 = 17.5 inches, which rounds up to 1/2 yard.

Worked example: a 90 x 108 inch queen

Perimeter: 2 x (90 + 108) = 396 inches, plus 10 = 406 inches.
Strips: 406 / 42 = 9.67, so cut 10 strips.
At 2 1/2 inch strips: 10 x 2.5 = 25 inches, or 3/4 yard.
At 2 1/4 inch strips: 10 x 2.25 = 22.5 inches, or 5/8 yard.

Notice that the narrower strip saves an eighth of a yard on a queen quilt. On small quilts the saving often disappears in the rounding.

Choosing a strip width

A 2 1/2 inch strip folded in half (double-fold binding) is the most common choice and finishes at a little under 1/2 inch on the front when sewn with a 1/4 inch seam. A 2 1/4 inch strip gives a slimmer, snugger edge and suits thinner battings. Thick or wool battings need a wider strip. Whatever you choose, make a short test piece first if you are unsure.

Common mistakes

Measuring the edges. Edges stretch; measure through the centre.
Using 44 inches as usable width. After selvages are removed, 42 is safer. If your fabric is narrower still, enter the real width in the calculator.
Forgetting bias binding needs more. These numbers are for straight-grain strips cut across the width. Bias binding for curved edges is cut differently and needs more fabric.

Let the calculator do it

The quilt binding calculator runs these steps for any size, strip width and fabric width. If you want to keep the numbers with the rest of the project, the backing and binding worksheet in The Quilt Planner walks through the same steps on paper.

Related tool: open the calculator.