Craft & baking

Quilt binding calculator

Plan your binding strips, diagonal joins and the fabric length to buy.

  • No sign-up
  • Calculated on your device

01 / Your quilt & binding

in
in
in

Width before folding. Each diagonal strip join uses one strip width.

in

Length of each square-ended strip after trimming selvages.

in

Includes final closure, corners and handling, not intermediate strip joins. Must be at least one cut strip width.

Round the total up to your shop’s cutting increment.

For square or rectangular quilts: straight-grain, square-ended strips joined with 45° diagonal seams. This does not calculate bias binding or pre-cut angled strips. Changing units converts your measurements.

02 / Your results

0.625 ydBinding fabric to buy0.5715 m equivalent
8 stripsCut each 2.5 in wide × 42 in longBefore shop rounding: 20 in of fabric (≈ 0.556 yd).
Binding length and diagonal join allowance
Binding lengthAmount
Quilt perimeter280 in
Finishing allowance12 in
Needed after strip joins292 in
Available after strip joins318.5 in
Extra joined length26.5 in

7 intermediate joins consume 17.5 in in total: one cut strip width per 45° join.

Your finishing allowance already includes 2.5 in for the final diagonal closure, leaving 9.5 in for corners and handling. That closing overlap is counted once.

How the calculation works

The target binding length is the quilt perimeter plus your finishing allowance. For n square-ended strips of usable length F and cut width S, overlapping at right angles and joining along 45° gives nF − (n − 1)S before final closure. The finishing allowance includes that closure. Fabric length to cut is n × S.

Try an example

A 60 × 80 inch quilt with 12 inches for finishing needs 292 inches of binding. Eight 42 × 2½ inch strips provide 318½ inches after seven joins. Cut 20 inches of fabric length, or buy ⅝ yard at ⅛-yard increments.

How to use this calculator

  1. Choose inches or centimetres and enter the quilt's finished width and height. Enter the usable fabric width after removing selvages.
  2. Set the width of each strip before folding and a finishing allowance for corners, handling and the final closing join. Choose your shop's purchase increment.
  3. Select Calculate binding. Cut the stated number of strips, then join their square ends at right angles with 45° seams. Review the usable binding length and rounded fabric purchase amount.

Common questions

Why does each diagonal join reduce the length?

Overlapping two square-ended strips at right angles and sewing across the overlap consumes one strip width in length. Eight 42-inch strips cut 2½ inches wide make 318½ inches after seven intermediate joins: 8 × 42 − 7 × 2.5.

What does the finishing allowance include?

It covers the final closing join plus the extra you choose for corners and handling. It must be at least one cut strip width. The calculator subtracts intermediate join losses separately, so the final closure must not be deducted a second time.

Can I use this for continuous bias binding?

No. This version counts straight-grain, square-ended strips joined on the diagonal. It does not estimate a continuous-bias tube, strips with pre-cut angled ends or binding for curved edges. Use the cut strip width, not the finished folded width.

Further reading: Fat Quarter Shop: joining and attaching quilt binding