Skein to Ball Calculator — Convert Between Yarn Formats

A skein (or hank) is yarn wound into a large loop and then twisted. It must be wound into a ball before knitting to avoid tangling. A ball is wound into a compact shape, either a round ball or a flat "cake". Some yarn is sold in pull-skeins that look like oblong cylinders and can be knit from directly.

No, you should not knit directly from an unwound hank/skein. The loops will tangle very quickly. You need to wind the hank into a ball using a ball winder and swift, or by hand around your fingers. Pull-skeins (oblong cylinders) are pre-wound and can be knit from directly.

You might split a large skein into smaller balls for two-at-a-time sock knitting, for colourwork where you need the same colour in multiple places, or when you want to alternate skeins every few rows to blend slight colour variations between dye lots.