Reference material
- Craft Yarn Council: standards and guidelines, including yarn-weight categories, hook sizes and crochet terminology.
- Craft Yarn Council: crochet gauge.
- Lion Brand: yardage per skein and yarn substitution.
References were consulted for terminology and general material-planning principles. The arithmetic examples, calculator code and explanations are developed for this website. We do not reproduce CYC chart graphics or downloadable symbols. The site is not affiliated with the organisations above.
Photograph
Homepage yarn photograph by Joy Ru on Unsplash, used under the Unsplash licence. The photograph is illustrative; it is not a test sample for the calculator examples, and photographed products are not sponsored recommendations.
Diagrams and colour studies
Square grids are generated directly from calculator inputs. They are simplified planning diagrams, not stitch charts, crochet instructions or photorealistic predictions. Written colour numbers and counts accompany the diagrams.
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