Crochet stitches are denser than knit stitches, so crochet projects generally use more yarn for the same finished size. This calculator already builds that difference in.
Crochet Yarn Yardage Calculator
Pick your project and yarn weight to get an estimated yardage range, then enter your yarn's yards-per-skein (on the label) to see how many skeins to buy.
Why a range, not one exact number? Actual yardage depends on your specific pattern, gauge, and size, so this is an estimate range, not a substitute for a pattern's own yardage requirement. Crochet typically uses about 25% more yarn than knitting for the same finished size, since crochet stitches are denser. This range already includes that adjustment. Buying at the high end of the range (and a little extra for swatching) avoids running short mid-project.
As a rule of thumb, crochet uses about 25% more yarn than knitting the same size project, since crochet stitches pack more yarn per square inch of fabric. Stitch choice matters too – a dense stitch like single crochet uses noticeably more yarn than an open, lacy stitch, so treat this as a starting estimate rather than an exact figure.
As with knitting, buy toward the high end of the estimated range, and try to buy all your skeins from the same dye lot up front if your project needs consistent color.