What is Yarn Weight Anyway?

Picture yourself browsing through The Stitchin’ Den, touching the yarn (who could help but touch), and instantly falling in love with a lovey color or super-soft texture.  Better yet, you find that perfect pattern (just the right cut or design) and you just itch to knit it.  Either way, making that perfect match of yarn and pattern is critical to the outcome of the final product.  A key factor in selecting the yarn is paying attention to the recommended weight.

Knit Check measuring gauge

To find just the right pattern for that special yarn or to find the right yarn for your favorite pattern, you need to keep a few things in mind: yarn weight, gauge, texture, composition, and cost.  Let’s think just about yarn weight and gauge in this post.  I like to look for the correct weight and gauge before I consider the other characteristics.  Yarn weight has to do with the thickness of the yarn and gauge with the number of stitches and rows knitted in a 4-inch square (swatch) on the suggested needle size.  I use a Knit Chek to count stitches on my swatch.  I like it so much, I own two!  The needle sizing holes are an added bonus as I use circular needles.  Mine are so well used that I have worn off the printing with the number sizes on them; so, I need to check their size using my handy little Knit Chek.

Yarn Ball Band showing weight needle size gauge

Really understanding what is meant by yarn weight can be a bit challenging.  There are so many weights of yarn and sometimes the names can vary depending on the brand of yarn.  Superfine, fingering, DK, sport, chunky, bulky, super chunky, etc. are common names.  Some yarn is also labeled with a number from 0 for superfine to 7 for super bulky.  Some yarn has both weight name and number.

Even if you are an experienced knitter or crocheter, it is possible to get confused by yarn weight.  Superfine and bulky yarns are pretty easy to distinguish but differentiating between sock (often referred to as fingering), sport and DK yarns can be a little trickier.  DK is a little bit thicker than sport; sport is a little thicker than sock (fingering).  By the way, DK stands for Double Knit (there does not seem to be a consensus on exactly why).  To get a great visual, check out the video below.  I really like the comparison of different weights of yarn and how they look in a swatch.

As you may notice from the chart below, there might only be a couple of gauge stitches different between say sport and DK yarns.  The number of stitches per inch will also differ depending on your personal knitting tension, the type of yarn, and needles you use.

Yarn Weight Chart

I usually knit right on gauge or a little tighter, in which case I have to go up a needle size to achieve recommended gauge.  Achieving gauge is critical.  A couple stitches more or less can add up in a garment.  For example, one extra stitch in a 4-inch swatch on a garment that is 40 inches around can add an additional inch.  Therefore, I take care to use the recommended yarn weight as a beginning point for my selection of yarn.  Below, you can see an example of such a recommendation from a poncho pattern and the info on the yarn band of the yarn I was thinking of using.

Materials: Lang Finn (75% wool, 25% acrylic; 88 yds/50g) - 12 balls
Needles: US #10 circular at least 24” long.
Gauge: 3.5 sts/in and 6 row s/in over rib pattern stitch after wet blocking.  

Aireado Ball Band

I did not use the brand of yarn listed to knit this poncho.  Both the recommended yarn and Aireado (my choice, pictured at right) are designated as bulky yarn even though the yardage for 100 grams is different.  Aireado has 283 yards per 3.5 oz. or 100 grams. The recommended yarn has 176 yards.  That might seem like a big difference and it is; however, that is due to the composition of the individual yarn.  The wool and acrylic blend in Lang Firm weighs more than the alpaca of Aireado.  Therefore, there are fewer yards in a skein of the wool/acrylic blend.  Despite the difference in recommended needle size, both yarns can achieve a gauge of 3.5 stitches per inch or 7 stiches per 2 inches.  It was close enough gauge for me to knit a swatch with the Aireado and check the gauge.  I used the suggested US 9 needle size on the yarn band to knit a swatch and ended up with too many stitches per inch.  My second swatch knitted on a US size 10 ended up with 3.5 stitches per inch – just what I needed.

Finished Poncho

I fell in love with Aireado, and I am still crazy about it.  Finding the right projects (I have knitted three) for this yarn took a little bit of searching and comparing.  I wanted the right weight and something with a little halo or fuzziness.  It was well worth the effort.

The bottom line is that yarn weight matters.  Bulky yarns produce thick fabrics that knit up faster and often require less yardage.  That is why they are fun to use to knit or crochet afghans.  Worsted produces a fabric of medium tightness and so is a go-to yarn for sweaters, and fine yarns make terrific shawls.  Read the information on yarn bands carefully.  Ask yourself if the designated yarn weight (worsted, bulky, sock, etc.) and the recommended gauge and needle size compare with the pattern that you want to knit.  Knit a swatch and check your gauge.  Experiment with going up or down a needle size.  Do you like the look of the fabric?  Is it dense enough?  The more you do this, the more you will learn about yarn and your own knitting tension.