How the calculations work

Every number comes from the block's geometry and the settings you choose. Here are the rules, so you can check them against your own.

Cut sizes

• Squares and rectangles: finished size plus 1/2".
• Half-square triangles: a square of the finished leg plus 7/8", cut once diagonally.
• Quarter-square triangles: a square of the finished long side plus 1 1/4", cut twice diagonally.
• Curves, diamonds, hexagons and wedges: no rotary formula, so these are cut from the true-size templates in the PDF.
• All seams are 1/4".

When a size falls between ruler marks

A 12" block on a 7-unit grid has units of about 1.714", which no ruler marks. The builder rounds those cuts up to the next 1/8", says so, and suggests the nearest block sizes that divide evenly. The center of a Square in a Square never lands on a mark, at any size, so plan to trim that block.

Yardage

Pieces are cut in strips across the fabric, using 40" of usable width unless you change it. The builder tries both strip directions and uses the shorter one, adds 10% for straightening and mistakes, then rounds up to the next 1/8 yard. Backing extends 4" past the quilt on every side. Binding is 2 1/2" strips with 20" extra for joins and corners. These figures are a guide, so check them before you buy or cut.

Knitting and crochet

Your stitch and row gauge decide everything. The starting count is your width times your stitches per inch, rounded to the nearest whole pattern repeat, and rows round up the same way. Starting gauges for each yarn weight are typical values, so measure your own swatch.

Yarn is a rough estimate, based on a rule of thumb for how much yarn a stitch of that size uses, plus 10%. Fiber and tension change it a lot, so buy extra. Crochet terms are US.

Your data

Your design is generated in your browser and is not sent anywhere. Most settings live in the page's address, which is what makes a share link work. Seeds and the palettes you save stay in this browser's local storage.

The designs

Blocks are drawn from geometry using traditional names. Layouts for the same name can vary between quilters and sources, so yours may differ from one you know.