Yarn Weight Chart

The single most useful number on a yarn label is the little numbered skein symbol. It tells you which category the yarn belongs to, which tells you what needle or hook to reach for, which tells you whether the pattern in your hand will work with the yarn in your basket. Everything else on the label is downstream of it.

Below is the complete standard, reproduced from the Craft Yarn Council's published system. We have not adjusted, averaged or simplified any of it - where a range looks wide, the range genuinely is that wide.

The full standard yarn weight system

How to read a range without getting it wrong

The gauge column is the definition and the tool column is a suggestion. That order matters and most people have it backwards. A yarn is category 4 because it knits at 16 to 20 stitches over 4 inches - not because the label says to use a 5mm needle. If you knit tightly, you may need a 5.5mm to land inside that range; if you knit loosely, a 4.5mm. Both of you are using category 4 yarn correctly.

This is also why two yarns that share a category can behave differently. Worsted covers a wide band. Red Heart Super Saver knits at 17 stitches over 4 inches on a 5mm needle; Patons Classic Wool knits at 20 stitches over 4 inches on a 4.5mm. Both are category 4. Swap one for the other in a pattern and your fabric changes, even though the label symbol is identical.

The categories people actually get stuck between

DK versus worsted (3 versus 4)

This is the most common substitution question in the craft, because the two categories overlap in practice. Category 3 tops out at 21 stitches per 4in; category 4 starts at 20. A yarn labeled light worsted sits on the seam. If a pattern calls for DK and you have worsted, you will get a bigger, denser garment unless you go down a needle size and recheck gauge - the full method is in how to substitute yarn.

Bulky versus super bulky (5 versus 6)

Category 5 runs 12 to 15 stitches per 4in; category 6 runs 7 to 11. That is close to a doubling of thickness across the boundary, and it is why a super bulky substitution into a bulky pattern goes wrong so visibly. Chenille blanket yarns such as Bernat Blanket sit firmly in category 6 at 8 stitches per 4in.

Fingering, sock and lace (0 versus 1)

Sock yarn is category 1, not 0, despite being routinely called fingering. Category 0 is genuinely finer - lace weight and 10-count crochet thread. If a sock pattern says fingering and the yarn says lace, you are two steps out, not one.

What the label does not tell you

The weight symbol says nothing about fiber, and fiber is what decides how the finished object behaves. A category 4 cotton and a category 4 wool knit to the same gauge and then do completely different things: the wool has memory and springs back, the cotton hangs and grows. That is a separate question, answered in the fiber guide.

It also says nothing about yardage. Two 100g skeins of category 4 yarn can differ by 50 yards or more depending on fiber density - wool is bulkier per gram than cotton. When you are buying for a project, count yards, never skeins. How much yarn do I need sets out the arithmetic.

Using this chart to buy tools

If you are buying your first set of needles or hooks, the chart tells you where to concentrate. Categories 3 through 5 - DK, worsted and bulky - cover the overwhelming majority of published patterns for garments, blankets and accessories. That is 3.75mm to 9mm in hooks and 3.75mm to 8mm in needles.

Any set that covers that band will handle almost everything you will make in your first two years. Sets that go far below 2.25mm are for thread crochet and lace, which is a different craft with different tools. See the needle size chart and hook size chart for the size-by-size detail, or go straight to the interchangeable needle sets and crochet hook sets we would buy.