Although I’ve mostly been stitching of late, and my old yarn review/knitters’ advice board/pattern website WiseNeedle that lasted for 13 years is but a distant memory, I have not given up knitting. I keep a sock project or two going at all times, and consult for my mom as her remote “knitting lady.” The patterns from WiseNeedle can all be found here, as can some of my advice, hints, and rants from the past, although the WiseNeedle question-answer board is gone. But of late I’ve seen quite a few complaints on knitting forums about yarn weights – confusion, botched projects, and misapprehension. I chime in and try to help.

First of all, the universal yarn weight system introduced by the Craft Yarn Council around 2004 continues to sow havoc. It’s misguided, untrustworthy, and has destroyed many knitters hopes and aspirations. To recap, this was the system that divided all yarns into numbered groups, initially 6, now expanded to 8:

The yarns within these groups are not instantly substitutable for each other because the definitions are overly broad. Here’s a breakdown:

	Group 0	Group 1	Group 2	Group 3	Group 4	Group 5	Group 6	Group 7
Type of Yarns in Category	Fingering, 10 count crochet thread	Sock, Fingering, Baby	Sport, Baby	DK, Light Worsted	Worsted, Afghan, Aran	Chunky, Craft, Rug	Bulky, Roving	Jumbo, Roving
Knit Gauge Range* in Stockinette Stitch to 4 inches	33-40 sts	27-32 sts	23-26 sts	21-24 sts	16-20 sts	12-15 sts	6-11 sts	6 sts and fewer
Recommended Needle in Metric Size Range	1.5-2.25 mm	2.25-3.25 mm	3.25-3.75 mm	3.75-4.5 mm	4.5-5.5 mm	5.5-8 mm	8-12.75 mm	12.75 mm and larger
Recommended Needle U.S. Size Range	000-1	1-3	3-5	5-7	7-9	9-11	11-17	17 and larger
Crochet Gauge Ranges in Single Crochet to 4 inch	32-42 double crochets	21-32 sts	16-20 sts	12-17 sts	11-14 sts	8-11 sts	5-9 sts	6 sts and fewer
Recommended Hook in Metric Size Range	Steel 1.6-1.4mm; Regular hook 2.25mm	2.25-3.5 mm	3.5-4.5 mm	4.5-5.5 mm	5.5-6.5 mm	6.5-9 mm	9-15 mm	15 mm and larger
Recommended Hook U.S. Size Range	Steel 6,7,8; Regular hook B-1	B-1 to E-4	E-4 to 7	7 to I-9	I-?9 to K-10 1⁄2	K-10 1⁄2 to M-13	M-13 to Q	Q and larger

^{(source: Craft Yarn Council’s http://www.yarnstandards.com/weight-system.html)}

To be fair, there are all sorts of caveats on this chart at the original site that include “Guidelines only,” “…always follow the gauge in your pattern,” and more. Even so, it’s wildly misleading.

The core of it (Groups 1-6) were created at the time that the industry thought that busy women had less time to knit and appreciated projects that finished up quickly. To compensate the “gauge creep” move was led by big craft yarn makers. Yarns that were formerly labeled Aran or Light Bulky were rebranded as Worsted, with the idea that fewer stitches per inch would make the projects zip along, This was especially evident among makers of mass market acrylics, and the heritage of that movement is seen in the groupings above. In fact it’s hard today to find a true worsted weight Worsted because most yarns labeled “Worsted” knit up to Aran gauge.

Now in a reversal because fiber of all types is getting more expensive, many makers are “slimming down” their yarns to keep project price points more attractive – less fiber = lower per skein price; and thinner yarns are now creeping into designations formerly reserved for heavier ones. This has resulted in a new round of confusion, once again long loved patterns no longer produce the same results as they did with yarn of prior years.

Regardless of yarn size fluctuations the basic flaw of this chart, however footnoted and expanded, remains. The yarn categories cover wide ranges of gauges, and are unsuitable as type descriptors or as guides for determining suitability for interchange.

Now. What is more useful?

Easy. The ancient Ply System.

Now note this as absolutely nothing to do with the actual number of plies a yarn contains. You can have a fat single, or a multi-ply extremely fine yarn. The ply system is based on comparison of the strand thickness of the yarn being described to a canonical batch of yarns that can be made by combining one or more strands of a mythical standard thickness yarn. That system has far more specificity to the standard gauges on yarn labels, and along with those gauges plus yarn fiber and loft (how airy or tightly twisted/dense the yarn is), is far more likely to result in good substitution choices. It also is a good guide for what happens when you double your yarn. In fact, the popular yarn weight “Double Knitting” (DK) refers to a yarn that is twice what used to be called “Knitting.” Knitting was the equivalent of today’s fingering or sock yarns. Two strands of fingering are still roughly the equivalent of today’s DK.

Ply System Number	Traditional Name	Standard Knitting Gauge over Stockinette (4 inches/10 cm)	Comments	Typical Examples (off the top of my head)
1	Cobweb		No consistent close knit gauge – used with variety of larger needles to maximize airy look.	Jamieson & Smith 1ply Cobweb
2	Lace		No consistent close knit gauge – used with variety of larger needles to maximize airy look.	Lopi Einband; Rowan Fine Lace; Jamieson & Smith 2ply Lace Weight
3	Light Fingering/Baby	32-36	“Baby” on the label is now near meaningless because in modern use it designates yarns in pastel colors and easy care fibers, regardless of gauge.	Brown Sheep Wildfoote; Peter Pan 3 Ply Baby; Red Heart Its a Wrap;
4	Fingering/Sock	28-32		Cascade Heritage Sock; Regia sock yarns; Opal sock yarns; Lang sock yarns
5	Gansey	26-28		Frangipani 5 Ply; Upton Guernsey Wool;
6	Sport	24-26		KnitPicks High Desert Sport; Herrschners 2 Ply; Lion Dotted Line
7			Not used
8	Double Knitting	22		Rowan Felted Tweed DK; Berroco Comfort DK; Wendy Supreme DK; Lion Ice Cream; Herrshners Baby Yarn
9			Not used
10	Worsted	20		Cascade 220; Plymouth Encore; Germantown Worsted; Plymouth Pima Rino; Sirdar Country Classic Worsted
11			Not used
12	Aran/Triple Knitting	18		KnitPicks Muse. Herrschners Worsted 8; Red Heart Roly Poly; Lion Crayola; Caron Simply Soft; Tahki Donegal Tweed
13			Not used
14	Bulky/	12-16		Plymouth Encore Chunky; Cascade 128; Lamb’s Pride Bulky; Lion Re-Tweed
15			Not used
16	Super Bulky	8-12		Malabrigo Rasta; Plymouth Encore Mega

Now again – caveats on density, fiber choice, and construction. Some examples:

• When worked, a tightly plied and twisted yarn will have a different drape than a fat single ply yarn, even if the fiber composition is the same.
• A 90% wool/10% acrylic blend will have a different feel than a 10% wool/90% acrylic blend. For best equivalency try to match fiber composition/mix proportions.
• And a cotton yarn and a wool yarn of equal weight will behave differently – enough differently to generally not sub one for the other without taking the extra mass and lack of elasticity of the cotton when compared to wool of equivalent size.
• In a delightful bit of industry internal obfuscation the term “worsted” in addition to being a yarn weight category also is used to describe a style of spinning. But not everything that’s labeled Worsted conforms to that specification.
• Some yarns can be knit down or up in gauge. For example a lofty 100% wool Aran with a “native gauge” of 18 st = 4 inches/10cm might also be able to be knit at worsted gauge 20 stitches = 4 inches/10cm. The drape will be different but it may be satisfactory for some purposes. Note that NOT ALL YARN can be manipulated this way, and lumping many adjacent weights into broad and misleading groups is just asking for trouble.

To sum up, please people, look beyond the CYC Yarn Group designation. Look at gauge, fiber, and density. And take guidance from these older systems. They were created by people who knew their wool and fiber, and there still is a lot of wisdom in them.