Tested tool guide
Tested browser tools
Checked August 16, 2026
What Quilt Fabric Calculator does, with a checked example
Quilt yardage math looks like area arithmetic, but fabric is sold in fixed widths by the yard, so a 12-inch finished block needs a 12.5-inch cut square and only three of those fit across a 42-inch width. This tool converts a quilt size and its parts - blocks, sashing, borders, backing - into yards, handling seam allowances, how many pieces fit across the fabric width, and rounding up to a cuttable increment. The surprise most quilters hit: backing a quilt wider than about 40 inches takes two seamed panels, roughly doubling the yardage a first guess would suggest.
Worked example
A concrete input and expected output from the current implementation.
Input
Blocks: 20 squares, 12 in finished. Quilt top: 48 x 60 in. Fabric: 42 in wide. Backing: 108 in wide.
->
Expected output
Blocks: 2.5 yd. Backing: 2 yd. Total: 4.5 yd.
Each block needs a 12.5-inch cut square (1/4-inch seams on all sides), and three fit across 42 inches, so 20 blocks take seven 12.5-inch strips: 87.5 inches, or 2.43 yards, rounded up to 2.5. The 48 x 60 top needs a 56 x 68-inch backing, which fits in one 108-inch-wide length of 68 inches, or 1.89 yards, rounded up to 2.