Yarn Weights Decoded: Names, Numbers, & How to Substitute Yarn

Is DK the same as 8-ply? Is aran just a fancy word for worsted? And why does your pattern ask for 350 grams when every label in the shop talks about yards?

If you've ever stood in front of a wall of yarn feeling like you need a decoder ring, you're in good company. Everyone's been there. It can feel like yarn has more aliases than a spy movie! The good news: Once you know how the naming systems line up, and how to interpret/translate the numbers on the label, using (and swapping!) yarns gets a whole lot less scary.

Here's everything you need to choose a substitute with confidence, plus the simple math for figuring out how much to buy.

In this guide

• Why yarn weights are so confusing
• The yarn weight chart
• The names that trip everyone up
• The number on the label that matters most
• How much of the new yarn do you need?
• How to choose a substitute yarn
• Yarns held together
• Find your match on our shelves
• Yarn weight FAQ

Why yarn weights are so confusing

"Weight" in yarn-speak is about how thick the strand is, not how much it weighs. And depending on where a yarn (or a pattern) comes from, that thickness might be described in three different ways:

• Numbers. The Craft Yarn Council's standard sorts yarn into categories from 0 (lace) to 7 (jumbo). You'll often see the number inside a little skein symbol on the label.
• Names. Fingering, sport, DK, worsted, aran, chunky, and so on. These are the words most knitters and crocheters use day to day.
• Ply. UK and Australian patterns often use ply: 4 ply, 8 ply, 10 ply. Confusingly, these numbers no longer tell you how many strands are twisted together. They're just names for a thickness.

Easy... right? On top of that, every brand interprets the categories a little differently. Two yarns can both say "DK" and still knit up differently.

The yarn weight chart

Here's how the systems line up. Bookmark, screenshot, or print this chart for your knitting bag!

Notice that the yardage ranges overlap. A thick DK and a thin worsted can be closer than two yarns that share a label. Keep that in your back pocket. It's about to matter.

The names that trip everyone up

Lace. The thinnest category. Many lace-weight yarns, especially fuzzy mohair blends, are designed to be held together with another yarn, which we'll get to below.

Fingering vs sock vs baby. These all live in under Super Fine (category 1). "Sock" yarn is usually fingering weight with a little nylon added for durability. "Baby" can mean category 1 or 2, so check the label.

Sport vs DK. Sport (category 2) is a touch thinner than DK (category 3). Fun fact: DK is usually equivalent to two strands of fingering-weight yarn.

Worsted vs aran. Both are Medium (category 4), but aran is usually a bit heavier. You can often swap one for the other, but your gauge swatch gets the final say.

Chunky vs bulky. Same thing, different side of the Atlantic. "Chunky" is the common UK name, and "bulky" is common in the US.

The number on the label that matters most

This might be the most important thing we say: When you're substituting yarns, look at the yardage, not the grams.

Grams tell you how much a skein weighs. Yardage tells you how much yarn you're actually getting. Different fibers have different weights, so 100 grams of one yarn can be a lot more (or a lot less) yarn than 100 grams of another. Here's proof, using five yarns currently on our shelves that are all labeled worsted:

You can see that 100 grams of Woolstok gives you about 50% more yarn than 100 grams of Sweater because cotton is a denser fiber than wool, so it changes the actual, physical weight of the finished product. Grams alone don't tell you the whole story. Most labels list the yardage (and often meters) per skein, the weight in grams, the fiber content, and a recommended gauge and needle size. Those last two are your best clues to how a yarn will behave. And remember: Less yarn isn't a bad thing; it's just a reflection of the fibers and grams.

Ravelry is a GREAT place to find yardage for yarns and patterns that don't explicitly state the info you need. It's a free community platform, digital database, and organizational tool for knitters, crocheters, spinners, weavers, and dyers. Ravelry has become a kind of historical database for knitters. When in doubt or struggling, go to Ravelry and see what info you can find from other knitters! (Note: You'll be asked to create an account to view the full site, but don't worry. It's free, and it's so worth it!)

Substituting yarn: How much do you need?

Here's where many knitters get tripped up, especially with patterns that list the yarn in grams instead of yards. Trust us, you're not the only one to wonder. Since different yarns pack different lengths into the same grams, you need to convert the pattern's amount into length first, then figure out how many skeins of your new yarn give you that length.

Don't worry. It's three simple steps and a calculator.

The three steps

1. How many skeins does the pattern use? Grams the pattern calls for ÷ grams per skein of the original yarn
2. How many yards is that? Number of skeins × yards per skein of the original yarn
3. How many skeins of the new yarn? Total yards ÷ yards per skein of your new yarn. Always round up.

Let's try it

Say your pattern calls for 600 grams of Woolstok, which comes in 50-gram skeins of 123 yards. You'd like to use Wooly Worsted instead, which has 95 yards per 50-gram skein.

1. 600 g ÷ 50 g = 12 skeins of Woolstok
2. 12 × 123 yds = 1,476 yards
3. 1,476 ÷ 95 yds = 15.5, so round up to 16 skeins of Wooly Worsted

Sixteen 50-gram skeins weigh 800 grams, not the 600 the pattern listed. If you'd bought 600 grams of Wooly Worsted, you'd run out somewhere around the second sleeve. (Ask us how we know. Common heartbreak.)

The same pattern with other yarns:

• Moonshine: 1,476 ÷ 123 = exactly 12 skeins. Grab a thirteenth for peace of mind.
• Sweater: 1,476 ÷ 160 = 9.2, so 10 skeins (1,000 grams)

Your turn!

• ____ g (pattern) ÷ ____ g per skein (original yarn) = ____ skeins
• ____ skeins × ____ yds per skein (original yarn) = ____ yards
• ____ yards ÷ ____ yds per skein (new yarn) = ____ skeins, rounded up

A few tips

• Use your size. Patterns list different amounts for each size, so start from the number for the size you're making.
• Don't mix units. If your pattern lists meters and your label lists only yards, convert first. But if the label lists both, some prefer to just use meters to eliminate some math. (One meter is about 1.09 yards, and one yard is about 0.91 meters.)
• Find the original yarn's yardage. The pattern usually names the yarn it was designed with. If the yardage isn't in the pattern, the yarn company's website will have it. (Don't forget to use Ravelry! See above for details.)
• Buy it all at once. Yarn is dyed in batches called dye lots, and colors can shift slightly from one lot to the next. Buying everything together keeps your project consistent. (Some yarn brands have dye lots so small this isn't really practical, but it's good to keep in mind and ask about when you're shopping).
• Consider picking up one extra skein. Some people swear by getting extra, and others swatch first. Since we know it can take a while to start (and complete) a project, we recommend swatching pretty quickly after you get your yarn to see how far it gets you. Making a blanket? Knit out the first skein and see how many inches you get. Will the yarn you purchased carry you to the end? Now you can answer this. If you don't need the extra but already bought it, you can return unwound, intact skeins within 30 days. (Just hold off on winding it until you're sure!)

Choosing a substitute yarn

So! In review, when choosing a substitute yarn:

1. Start with the same weight category. If the pattern calls for a worsted, start your search with worsteds (and maybe arans).
2. Compare yards per 100 grams. The closer the substitute is to the original, the more likely it is to behave the same way. If a yarn's label lists a skein that isn't 100 grams, divide the yardage by the grams and multiply by 100.
3. Think about fiber. A yarn can match on paper and still make a very different fabric. More on that in a moment.
4. Swatch. Knit or crochet a gauge swatch, wash it the way you'll wash the finished piece, and measure. It's the only real proof that a substitute will work.

Why fiber matters
Use the chart below as a reference for how various natural fibers behave differently as you knit and then wear them. We've already discussed this a bit, but consider this your cheat sheet for future projects:

For example, back to our worsted yarns: Moonshine matches Woolstok's yardage exactly. But, Moonshine's alpaca and silk give it more drape than Woolstok's all-wool squish, so a sweater made with each would hang differently. Same yardage, different personality.

Yarns held together

Some patterns call for two yarns knit together as one strand, often a wool plus a fuzzy mohair. Using them together makes a thicker yarn with the best of both: the wool's structure and the mohair's halo. If you're substituting for a different yarn than your pattern calls for, run the math separately for each yarn. Two lace-weight mohairs, for example, can be surprisingly different!

Find your match on our shelves

A few of our favorites in every weight:

• Lace and mohair: Isager Silk Mohair
• Fingering and sock: Isager Tweed, Tough Love Sock
• Sport: Ewe So Sporty, Fleck
• DK: Scout, Plush DK from Plucky
• Worsted: Lucky Tweed, Woolstok, Wooly Worsted, Sweater
• Aran: Woolstok Tweed
• Bulky: Baa Baa Bulky, Alpachino Merino
• Super bulky: Big Merino Wool, Sequoia

Not sure which one fits your pattern? Bring it in (or email us at hello@pintuckandpurl.com), and we'll help you find a match, run the numbers, and send you home with exactly what you need. Comparing yarns is one of our favorite things to do.

Happy knitting!
Yarn substitution can feel like a math test you didn't study for, but it really comes down to three ideas: Match the weight, compare the yardage, and swatch. Do those, and you're free to knit (or crochet) any pattern in the yarn you love most. And if you ever get stuck, we're always happy to help.

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Yarn weight FAQ

What's the difference between DK and worsted?  DK (category 3) is thinner than worsted (category 4). DK typically knits at 21–24 stitches per 4 inches, and worsted at 16–20.

Is aran the same as worsted?  Not quite. Both are category 4, but aran is usually a little heavier. They can often be swapped, but swatch to check your gauge.

What weight is sock yarn?  Most sock yarn is fingering weight, category 1 (Super Fine), often with nylon added for durability.

Why does my pattern list grams instead of yards?  Many patterns, especially from European designers, list yarn by weight. To substitute, convert the grams into yards using the original yarn's label, then work out how many skeins of your new yarn you need.

Can I substitute a yarn from a different weight category?  Sometimes, but it's risky. Your fabric and gauge will likely change. Make sure you like your gauge swatch, and you may need to do some extra math. This is more advanced, so if you're a beginner, stick with the recommended weight category.