The numbers behind the colors.

This is a local prototype. Arithmetic tests and real crochet validation are different things.

Yarn for each color

Body yarn = sum of each style’s square count × its measured consumption for that color.

Needed yarn = body yarn × (1 + body allowance / 100) + your finishing yarn estimate.

Shortage = needed yarn minus available yarn, with a minimum of zero. Finishing yarn does not receive the body allowance again. A blank finishing entry is omitted and labeled as such.

A worked arithmetic example

Style 1 uses 4 g red and 2 g blue. Style 2 uses 1 g red and 5 g blue. Four of Style 1 and two of Style 2 use 18 g of each color. A 10% body allowance gives 19.8 g each. Adding 5 g of red finishing yarn makes red 24.8 g. If only 10 g blue remains, the blue shortage is 9.8 g.

This is an illustrative calculation, not a measured finished project.

Dimensions

Width = columns × square side + (columns − 1) × join gap + 2 × border width. Height uses rows in the same formula. These dimensions assume consistent squares and joins.

Units & rounding

Calculations use grams and centimeters internally. One ounce is 28.349523125 g; one inch is 2.54 cm. Switching units does not round stored measurements. Displayed totals are rounded; shortages round up to 0.1 g or 0.01 oz so a small shortage does not disappear.

What this version does not know

It cannot predict tension, substitute yarns, infer the weight of a border, or guarantee you have enough yarn. It supports rectangular arrangements of equal-sized square motifs. It has not yet been validated with real crochet participants or physical projects. The example uses synthetic data.