Work out crochet yarn requirement instantly with clear inputs, formula shown and shareable results.
Crochet fabric weight scales with area, so the requirement is the finished area divided by 100 times the grams per 100 square centimetres measured from a swatch. Crochet uses roughly a third more yarn than knitting for the same area, which is why substituting a knitting pattern's yardage leaves you short.
Yarn weight
grams = width x length / 100 x grams per 100 cm2
Yarn length
metres = grams / 100 x metres per 100 g
grams = width x length / 100 x grams per 100 cm2. Crochet fabric weight scales with area, so the requirement is the finished area divided by 100 times the grams per 100 square centimetres measured from a swatch.
Crochet uses roughly a third more yarn than knitting for the same area, which is why substituting a knitting pattern's yardage leaves you short.
Enter finished width, finished length, yarn weight per 100 cm2 of fabric, yarn length per 100 g. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.