Yarn substitution calculator: how many skeins of a different yarn?

The yarn substitution calculator above tells you how many skeins of a different yarn to buy for a knitting or crochet pattern. A skein is the wound bundle a yarn is sold in. The calculator works out the total yards the pattern needs from its own yarn, then counts skeins of your substitute to cover them. It also compares the two yarns’ yards per gram: the yards on a label divided by its grams. It gives no “good match” or “bad match” verdict: only a swatch can tell you that, so swatch before you buy.

How to use the yarn substitution calculator

1. The pattern’s yarn: type the yards and grams per skein from the yarn the pattern names. The pattern or the yarn company’s page lists them.
2. What the pattern calls for: pick “A number of skeins” and type the count, or “Total yards” if the pattern gives yardage.
3. Your substitute yarn: type its label’s yards and grams per skein.
4. Read the skein count, then the yards-per-gram comparison under it, and check each line of “Show the math”.

The calculator opens on a made-up example: a pattern that calls for 5 skeins of a 220 yd / 100 g yarn, so 1,100 yd, and a substitute with 200 yd per 100 g. That substitute has 9.1% less yardage per gram, and you need 5.5 of its skeins, rounded up to 6.

Match the yards, not the skeins or the grams

A pattern’s skein count is in its own yarn’s skeins, and a skein of another yarn may hold more or fewer yards. Lion Brand’s support page on yardage puts it this way: “The new ball or skein may weigh more or less; checking the yardage allows you to buy the required amount of yarn.”

Weight in grams doesn’t settle it either. Lion Brand’s blog, on swapping yarns: “Go by yardage, not weight, and you’ll be fine.” Purl Soho, a yarn shop, says the same and gives an example: if a pattern needs “three 200-yard skeins (600 total yards)” and your yarn comes in 100-yard skeins, you need 6 skeins.

Skein sizes can change even within one yarn. When a reader ran short on a Lion Brand pattern, the company replied on Wool-Ease Thick & Quick’s page that the pattern “was originally made in our Wool-Ease Thick & Quick Bonus Bundle skeins, which had twice the yardage of the regular Wool-Ease Thick & Quick skeins.”

A made-up example: the same 5 skeins of 220 yd / 100 g, swapped for a yarn sold as 110 yd / 50 g skeins. The two have the same yardage per gram, but you need 10 skeins, because each holds half the yards.

What yards per gram tells you, and what it doesn’t

Yards per gram compares two labels on one footing, whatever their skein sizes. Our assumption: a big difference is a clue that the substitute may be a thicker or thinner yarn. With the pattern yarn at 220 yd / 100 g:

These labels are made up. Open each row in the calculator: 250 yd, 200 yd and 100 yd.

It’s only a clue, because fiber changes it too. Lion Brand’s blog explains: “different fibers weigh different amounts. Cotton and silk, for instance, are much heavier than wool, so you’ll get much less yardage per pound.” Purl Soho gives a case: two 100% wool yarns with the same 135 yards per 100 grams have “a decent chance” of a similar gauge, it says, but that’s “much less likely” for 135 yards of cotton.

That’s why the calculator draws no line between a close match and a poor one. The only cutoff we found came from one blog, and we couldn’t confirm its units, so we don’t use it.

Check the weight category, then swatch

Start with yarn weight, which means thickness, not grams. Lion Brand’s blog: “You will have much better luck substituting yarns of the same weight category.” Look up both yarns on the yarn weight chart; no label on one of them? See how to tell yarn weight.

Then swatch: knit or crochet a small test square with the substitute and measure your gauge, the number of stitches in 4". Purl Soho says to wash the swatch the way you’ll wash the finished piece, and to match “the pattern’s gauge, not the gauge listed on the suggested yarn label.” The gauge calculator turns your swatch into stitch counts.

Our advice: if your substitute only gets gauge on a different needle or hook, or you change the pattern’s gauge, the pattern’s yardage may no longer hold. Weigh your swatch and run the yarn calculator for the yards your fabric needs. Purl Soho’s reminder for a changed gauge: “don’t forget to make sure you have enough yarn for the adjusted gauge!”

Fiber and ply change the fabric

Matching yardage and gauge doesn’t make two yarns behave alike. Purl Soho: “Changing the fiber of the yarn used for a pattern makes a huge difference to the feel, drape, and look of the finished piece.” Lion Brand’s blog suggests like for like, “wool for wool, cotton for cotton, etc.”

Ply counts too. Plies are the strands spun together into a yarn, and Purl Soho says “The more plies a yarn has, the rounder and stronger it will be and the more clearly it will show individual stitches.” A swatch shows you all of this at once, which is one more reason to make one.

FAQs

Can I use cotton instead of wool?

You can, says Lion Brand’s blog, but know how each behaves first: “wool is springy and elastic, while cotton is neither”. Compare the yardage here, then swatch.

Can I hold two strands together to substitute a thicker yarn?

Purl Soho lists pairings, such as “2 strands of fingering weight = DK weight”, and adds: “These are guidelines only”. This calculator counts single strands, so for a yarn held double, swatch it held double and work out the yardage with the yarn calculator.

Why doesn’t the calculator say whether my yarn is a good match?

No source we could check gives a tested cutoff for “close enough” yards per gram, and fiber changes the figure, as the section above explains. The calculator shows the difference; your swatch decides.

Should I buy extra yarn?

Our advice: buy every skein at once, all with the same dye lot (the batch number on the label). The skein count here covers the pattern’s yardage with no extra, so if you want a margin, the yarn calculator adds one to your own swatch’s figures.