Quilt Fabric Calculator

Type your finished quilt size and block size, and watch the layout and fabric estimate update as you go.

📖 How it works & FAQ

Finished quilt width (in)

Finished quilt height (in)

Block size, finished (in)

Seam allowance (in)

—Total blocksenter dimensions

—Fabric neededbased on 42″ usable width

—Cut size per blockincludes seam allowance

Plan your quilt before you cut

A quilt top is a grid of squares, so the fabric math comes down to three questions: how many blocks fit across and down, how big each block must be cut, and how much yardage that adds up to. This calculator answers all three the moment you type. Enter the finished width and height of the quilt, the finished block size, and your seam allowance, and it lays out the grid and estimates fabric for you.

How the numbers work

The number of blocks across is your quilt width divided by the block size, rounded up; the number down is the height divided by the block size, rounded up. Multiply the two for total blocks. Each block is cut larger than its finished size so the seams disappear into the quilt: cut size = finished block + 2 × seam allowance. A 12″ block with a ¼″ seam is cut at 12.5″. Yardage assumes 42″ of usable fabric width — we fit as many cut squares across that width as possible, stack the rows, and round up to the nearest eighth of a yard.

How to use it

Enter the finished width and height of your quilt in inches.
Enter your finished block size (all blocks assumed equal).
Enter your seam allowance — ¼″ is standard for quilting.
Read the live grid preview, total blocks, cut size, and yardage. Buy a little extra for squaring up and shrinkage.

FAQ

Why does the yardage look generous?: It counts one fabric for all blocks laid on 42″ goods. If your blocks use several fabrics, divide the count and buy per fabric.
Does this include borders, sashing, or backing?: No — it covers the block tops only. Add yardage separately for sashing, borders, binding, and backing.
What seam allowance should I use?: ¼″ (0.25) is the quilting standard. Some piecers use a scant ¼″; the cut-size math stays the same.
Are these figures exact?: These are estimates for planning, not professional advice. Always buy a little extra and confirm against your pattern before cutting.