About Craft Sums

Craft Sums is a set of free calculators for the buying decisions in a craft room: how much resin for the pour, how much backing for the quilt, how many yards for the pieces or the curtains, what size Aida for the chart, how much wax and fragrance for the batch, how many skeins for the blanket, and how to cast on for your own gauge. Each one shows the rule it uses and a table, so the answer can be checked, or learned.

The conventions

Resin is area times depth, with a flood coat at one-eighth of an inch and ten percent added for the cup and the run-off. Quilt backing is the top plus four inches on every side, pieced across a 42-inch width with the fewest seams, or one length of 108-inch wide backing; binding is the perimeter plus ten inches in strips cut across the width. Fabric yardage counts how many pieces fit across the usable width and how many rows that makes. Cross-stitch size is stitches divided by count, with evenweave stitched over two. Candle wax is the container's fluid ounces times a fill factor times the wax's weight per fluid ounce, fragrance as a percentage of that wax. Yarn is yards per square inch by yarn weight, with crochet using about a third more than knitting. Gauge adjustment is the ratio of your stitches per four inches to the pattern's.

What this site doesn't do

It doesn't store what you enter, require an account, or know your materials. Resins differ in mix ratio and maximum pour depth, waxes in fragrance load, yarns in how far they go; the manufacturer's label and your own swatch or test batch outrank any number here. Follow the safety guidance on the products you use.

Corrections

If a rule, convention or table here is wrong, email hello@craftsums.com. The maths is stated on each page so a correction can be checked against it.