How to calculate fabric yardage for a quilt

6 min read · Updated October 28, 2026

Buying too little fabric means hunting for the same print months later; buying too much fills the stash. Here is the method Quiltkit uses, step by step, so you can check any pattern by hand.

The four numbers you need

the finished size of each piece (what you see once the quilt is sewn);
the seam allowance: ¼ in (0.6 cm) on every side, the quilting standard;
the usable width of the fabric: quilting cotton is sold 42 to 44 in wide (about 110 cm), selvages removed;
how many pieces of each size you need.

1. From finished size to cut size

Add ½ in to each dimension of a square or rectangle: two seam allowances of ¼ in. A 2 in finished square is cut 2½ in.

Triangles need more: add ⅞ in to the finished side of a half-square triangle unit, and 1¼ in for a quarter-square triangle unit, when you cut them from squares.

2. Pieces per strip

Cut strips across the full width of the fabric, as tall as one piece. Divide the usable width by the width of a piece and round down: that is how many pieces fit in one strip.

3. Number of strips

Divide the number of pieces by the pieces per strip and round up. The yardage is the number of strips multiplied by their height.

4. Round up, then add a margin

Fabric is sold by the ⅛ yard or by 10 cm: round up to the next step. If you prewash your fabric or want room for a cutting mistake, add a few inches.

A worked example

You need 80 squares of 2 in finished size, in a fabric 110 cm (43¼ in) wide.

Cut size: 2 + ½ = 2½ in.
Pieces per strip: 43¼ ÷ 2½ = 17.3, so 17 squares.
Strips: 80 ÷ 17 = 4.7, so 5 strips.
Length: 5 × 2½ = 12½ in, that is 31.75 cm.
Rounded up: ⅜ yard, or 40 cm.

Backing and binding

The backing usually extends 3 to 4 in beyond the quilt top on every side, to leave room for quilting. For binding, quilters often cut 2¼ to 2½ in strips, enough for the whole perimeter plus about 12 in for joins and corners.

Let Quiltkit do the math

Quiltkit applies exactly this method to every fabric of your quilt and shows its assumptions on screen. You also get a cutting plan per fabric, to see where each piece comes from in the strips.