Yarn Substitution Calculator

How rounding works

For each yarn, the number of skeins is your required yardage divided by the yards per skein — then always rounded up. If a pattern needs 1,400 yards and a yarn comes in 220-yard skeins, that's 6.36 skeins, which rounds up to 7. You can't buy part of a skein, and being even a few yards short with no more of the same dye lot available is far worse than having a little left over. So the calculator never rounds down, even when the shortfall is tiny.

Reading the comparison

Each yarn gets its own card showing skeins to buy, total yards purchased, and the leftover yards (waste). If you enter a price per skein, you'll also see total cost. There's no single "best" answer — it depends on what you're optimizing for. Lowest waste matters when a yarn is expensive or hard to get, or when you hate having odd partial skeins in your stash. Lowest cost matters when you're on a budget and don't mind some leftovers. A yarn with more yards per skein often wastes more (you overshoot by a bigger chunk on the last skein), so the cheapest option per skein isn't always the cheapest for your project. The cards stay in the order you entered them so you can scan by your own priority.

Tips for substituting yarn

• Substitute within the same weight class (worsted for worsted, DK for DK) — yards-per-skein math can't fix a gauge mismatch. If your substitute knits up at a different gauge, run the numbers through the gauge converter first.
• Blocking can shift your finished yardage by roughly 5%; if a comparison is close, lean toward the option with more leftover.
• Buy all of one yarn from the same dye lot — leftover yards are no help if the second batch doesn't match.
• Save a ball band from any yarn you love; the yards-per-skein figure on it is exactly what this calculator needs next time.