Math you can inspect
Knit It Once is a calculation workspace for knitters and crocheters. The calculators are the product; the guides explain when and how to use them.
Methodology
Each calculator exposes its formula, units, assumptions, and known limitations. Calculation code is kept separate from the interface and covered by automated tests so changes can be checked without relying on visual output alone.
Local by design
Calculator inputs and project details stay in your browser. No account is required. Optional anonymous usage analytics, when configured, load only after consent and never include calculation values or project notes.
Corrections
A transparent correction is more useful than pretending craft math is infallible. Material formula and content changes are recorded in the changelog, and calculation problems can be reported through the contact page.