Yarn Weight Chart: The Complete Guide to Yarn Weights, Ply & Conversions

Have you ever found the perfect pattern, only to realize the recommended yarn is discontinued? Or pulled a gorgeous orphan skein out of your stash with no ball band and no idea what it is? Both problems come down to one thing: yarn weight.

Yarn weight has nothing to do with how much the ball weighs. It describes how thick the strand is — and it's the single most important factor in whether your finished project matches the pattern. Get it right and substitution becomes easy. Get it wrong and a worsted-weight sweater turns into a stiff, oversized tent.

Below is the complete Craft Yarn Council Standard Yarn Weight System chart, plus the practical stuff most charts leave out: how to convert UK and Australian ply numbers, how to identify an unlabeled skein from its grams and meterage, how to measure wraps per inch, and which weight actually works best for the project you have in mind. After thirty-plus years of helping knitters and crocheters substitute yarn at our Northampton store, these are the questions we field most.

The Complete Yarn Weight Chart

The Craft Yarn Council numbers yarn weights from 0 (Lace) to 7 (Jumbo). You'll see these numbers inside a little skein symbol on most modern ball bands. Knitting gauge is measured over 4 inches in stockinette stitch; crochet gauge over 4 inches in single crochet.

Crocheting? The crochet hook size chart breaks the hook column out in full, including steel hook sizes for thread and lace work.

UK & Australian Ply Conversion

This trips up more people than anything else in yarn substitution. If you're following a British or Australian pattern — or you've bought yarn from an overseas dyer — the "ply" number is a weight category, not a count of how many strands are twisted together. A modern "4 ply" sock yarn might actually be made of two or three plies. The name is historical.

The two that catch people out: UK Aran is not the same as US Aran — in the UK it maps to standard worsted, while American yarn companies often use "Aran" for something a little heavier. And Australian 8 ply means DK, not worsted, even though "8" sounds substantial. If an Australian pattern calls for 8 ply and you reach for worsted, your gauge will run large.

Identify Yarn Weight From Grams & Meterage

This is the trick for stash skeins with a partial label, and for overseas patterns that specify "50g / 125m" instead of naming a weight. Yarn weight correlates directly with length per unit of mass: thinner yarn packs more meters into the same 50 grams.

To compare any two yarns, normalize to meters per 50g. If your label says 100g / 200m, halve it — that's 100m per 50g.

Worked examples using the numbers people actually search for:

• 50g / 100m → DK weight (3). This is the classic European DK put-up.
• 50g / 125m → Sport weight (2), sitting right in the middle of the range.
• 50g / 150m → Heavy fingering to light sport — the awkward border. Swatch this one.
• 100g / 200m → halve to 50g / 100m → DK weight (3).
• 100g / 400m → halve to 50g / 200m → Fingering / sock weight (1). Standard sock skein.

The Wraps Per Inch (WPI) Method

When there is no label at all, WPI is the most reliable answer. It's the technique handspinners use, and it takes about a minute.

1. Find something with a straight edge and a known width — a ruler works, but a pencil or a knitting needle laid against a ruler is easier to handle.
2. Wrap the yarn around it in a single layer for a full inch. Don't stretch it, and don't leave gaps: the strands should sit side by side, just touching.
3. Count the wraps in that inch. That's your WPI.
4. Do it twice more in different spots along the strand and average the three. Yarn is not perfectly uniform, and a single count on a thick-and-thin section will send you one whole category off.

Match your number to the chart:

So if you counted 11 wraps per inch, you're holding a DK weight yarn — grab a US 6 needle and expect around 22 stitches over 4 inches.

Best Yarn Weight for Your Project

The chart tells you what a yarn is. This section tells you what to reach for when you're starting from the project instead. Crochet eats roughly 30% more yarn than knitting at the same weight, so if you're crocheting, read this alongside our guide to choosing yarn for crochet.

Socks → Fingering (1)

Almost every sock pattern is written for fingering-weight yarn on US 1–2 needles, at a tight 8–9 stitches per inch. That density is the point: socks live inside shoes and take more abrasion than anything else you'll make. Look for a nylon content of 20–25% in the blend — it's what keeps heels from wearing through in a season. Browse sock yarn →

Baby blankets → DK (3) or Worsted (4)

DK gives you a blanket that drapes and folds into a diaper bag; worsted gives you one that works up in half the time. Either way, choose something machine washable — this is the single most common regret we hear about handmade baby gifts. Shop baby yarn →

Adult sweaters → DK (3) to Worsted (4)

Worsted is the friendliest first-sweater weight: fast enough to stay motivated, fine enough to look like a real garment. DK is where you go for something you'll actually wear under a coat. Cascade 220 is the classic worsted workhorse for a reason — it blocks out beautifully and comes in a hundred-plus colors, so you can find a match for almost any pattern photo.

Shawls & wraps → Lace (0) to Fingering (1)

Lace and fingering are what make blocking dramatic. A lace shawl grows by a third when you pin it out wet, and the open stitch patterns only read clearly at a fine gauge. On worsted, the same chart turns into a blanket.

Hats & cowls → Worsted (4) to Bulky (5)

Bulky is the reason a hat can be a one-evening project. Worsted holds ribbing better if you want a brim that stays snug over time.

Amigurumi → Worsted (4), cotton, tight gauge

Here's the rule that surprises new crocheters: use a hook smaller than the ball band recommends — usually a 3.5–4 mm hook on worsted cotton. A hook with a sharp, well-defined throat makes that tight gauge much easier to hold — our tested hook picks note which ones do it best. You want a fabric so dense that stuffing can't peek through. Cotton also holds a crisp shape where wool goes soft and saggy. Shop cotton yarn →

Dishcloths & market bags → Worsted (4) cotton

Worsted cotton is the whole category here. It's absorbent, it survives the washing machine indefinitely, and it doesn't stretch out of shape when a bag is loaded with groceries.

Chunky throw blankets → Super Bulky (6) to Jumbo (7)

Budget more yarn than you think. Super bulky eats yardage fast — a throw can run 1,200+ yards, and because dye lots are large and irregular in these weights, buying short and reordering later is genuinely risky. Shop super bulky →

How to Substitute Yarn Safely

Matching the weight category is step one, not the whole job. Here's the order we walk customers through at the shop.

1. Match the gauge, not the label. The pattern's stated gauge over 4 inches is the real specification. Two yarns in the same category can be a full stitch apart per inch.
2. Compare yards per 100g. This is the most useful number on the ball band and the one most people ignore. If the pattern's yarn is 220 yds/100g and yours is 180 yds/100g, yours is heavier — expect a denser fabric and to run out sooner.
3. Think about fiber behavior, not just thickness. Wool has memory and springs back; cotton and linen have almost none and will grow under their own weight. A cotton substitute in a wool sweater pattern will hang longer on the body after a few wears.
4. Swatch and block it. Knit at least 4×4 inches, wash it the way you'll wash the finished object, and measure it dry. Superwash wool in particular can relax significantly after its first bath — a swatch that measured on-gauge straight off the needles can come out an inch wider.
5. Buy one extra skein. Heavier substitutes consume more yardage, and dye lots don't wait around.

Frequently Asked Questions

What does "yarn weight" actually mean?

It refers to the thickness of the yarn strand, not how much the ball weighs. The Craft Yarn Council sorts yarn into eight categories numbered 0 (Lace) through 7 (Jumbo), and that number is what patterns are written around.

What weight is 4 ply yarn?

In the UK and Australia, 4 ply means Super Fine — US fingering or sock weight, category 1. It knits at 27–32 stitches over 4 inches on 2.25–3.25 mm needles. Note that "4 ply" describes the weight category, not the number of strands twisted together.

Is 8 ply the same as worsted?

No — this is a common and expensive mix-up. Australian 8 ply is DK weight (category 3). Worsted is category 4, equivalent to Australian 10 ply or UK Aran. Substituting worsted for 8 ply will throw your gauge off and make the finished piece run large.

What yarn weight is 50g / 100m?

That's DK weight (category 3). To identify any yarn this way, convert the label to meters per 50 grams: roughly 90–120 m is DK, 120–175 m is sport, and 175–230 m is fingering. The method is reliable for wool but less so for cotton and silk, which are denser — use wraps per inch for those.

What weight is 11 WPI yarn?

Eleven wraps per inch puts you in DK weight (category 3), which spans 11–12 WPI. Wrap the yarn around a ruler in a single unstretched layer, count the strands in one inch, and average three separate measurements — a single count can land you a whole category off.

What is the best yarn weight for socks?

Fingering weight (category 1) on US 1–2 needles, worked at 8–9 stitches per inch. Choose a blend with 20–25% nylon for durability at the heel and toe.

Can I substitute a different yarn weight than the pattern calls for?

You can, but the finished measurements will change and you'll need to recalculate stitch counts. For a first substitution, stay in the same category and match the pattern's gauge with a blocked swatch. If you do move a category, expect to adjust the pattern math — and check yardage, since heavier yarn eats more of it.

Is Aran the same as worsted weight?

Nearly. UK Aran maps to US worsted, category 4. American companies sometimes use "Aran" for a slightly heavier yarn at the top of that category, so compare yards per 100g rather than trusting the name.

Still not sure what you're holding? Bring it to us. Our staff in Northampton have been matching mystery skeins to patterns for decades, and we're happy to help by phone or email too. Browse yarn by weight to start your next project with confidence.