UNDERSTANDING YARN WEIGHTS

Many patterns call for a specific yarn to be knit at a specific gauge. If that exact yarn is not available we have to have a way to know what other yarn might be appropriate. Just getting the gauge is not enough. We want to try and recreate the exact fabric.

I can use a large enough needle that I can get a gauge of 4 sts/inch with a lace weight yarn, a sport weight yarn or a worsted weight yarn. If the pattern is a lace shawl then most likely a lace weight yarn was used. If the pattern was a cabled cardigan than either a worsted weight yarn or an aran weight yarn was probably used. Even if you get the same gauge a cabled sweater from lace weight yarn would definitely not have enough body to be anything other than a drapy shawl.

In the US the Yarn Craft Council is trying to get all pattern writers, magazines and yarn labels to use a uniform symbol to mark yarn weight.

Standard Yarn Weight System

Categories of yarn, gauge ranges, and recommended needle and hook sizes
Yarn Weight Symbol
& Category Names / / / / / / /
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
Knit Gauge
Range* in
Stockinette
Stitch to 4 inches / 33–40**
sts / 27–32
sts / 23–26
sts / 21–24
st / 16–20
sts / 12–15
sts / 6–11
sts
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 mm
and
larger
Recommended
Needle U.S.
Size Range / 000–1 / 1 to 3 / 3 to 5 / 5 to 7 / 7 to 9 / 9 to 11 / 11
and
larger

You can see from this that the chart gives you the normal gauge (meaning a stockinette swatch that has body but is neither too stiff or too drapey) as well as the needle range usually used to knit the yarn.

So if you are familiar with this chart and have a knitting pattern that uses a yarn you have never heard of you can make an educated guess as to the yarn weight from the needle size and gauge.

These are only guidelines however. You need to see for yourself what gauge you get with a particular yarn. Manufactures call some yarns DK that I don’t think are even thick enough to be called sport. I think they knit better to fingering gauge. One example of this is Lavold Silky Wool. They call it DK I like it knit on size 3 – 4 US.

One of the best ways to determine if a yarn is the same weight and will knit up as the pattern calls for is to compare yardage in a similar weight skein.

In order for this to be accurate the yarn composition must be identical. You can not compare yardage in a 50 g skein of mohair to a 50 g skein of cotton. Cotton is much heavier and will have many fewer yards but both yarns could be called ww and both could easily knit to the same gauge.

If you have two 50g skeins of 100% wool they will usually have approximately the same yardage if they are the same thickness. The exception to this is comparing a plied yarn to a single. A single will be lighter and loftier and will probably have more yardage, it may appear thicker but will compress more when knitting on smaller needles. So it could be knit from DK to bulky perhaps.

Standards have been developed for wool so all labeling must conform to yards per lb as established in order to be called a certain weight. As you can see from the chart below there is a variance in yards per lb which is caused by loftiness of the yarn such as single vs plied.

Weight / Yards/lb / Yards/50g / Wraps/inch
Lace / 2600+ / 287 / 18+
Fingering / 1900-2400 / 209-265 / 16
Sport / 1200-1800 / 133-198 / 14
Worsted / 900-1200 / 99 -132 / 12
Bulky / 600-800 / 66-88 / 10
Very bulky / 400-500 / 44-55 / 8 or fewer

You can tell from this table that there can be sport weight yarn and ww yarn both legally labeled as such with the same yardage per pound. This is where the new terminology is often used – at the over lap areas. A yarn that has 1200 yards per lb would probably be labeled as DK these days. This is the same as heavy sport or light worsted.

The same thing happens with yarns with between 800-900 yards per lb instead of being worsted or bulky they might be called Aran weight or Heavy Worsted.

Wpi which means wraps per inch is a good way to tell what weight an unknown yarn might be. It is also used by handspinners to label their yarns. Take a ruler and wrap the yarn around it, not too tight, not to loose, lining up each wrap next to the last with no spaces between them and no overlapping. Do this for exactly 2 inches, then count how many wraps there are. Divide this number by two to get the "wraps per inch". Once you know the wraps per inch, you can figure out the weight (and can estimate the yardage) of the yarn based on the table above.

It needs to be noted that the term "worsted" is also a term that describes the way the yarn is spun (from combed top, very smooth, with all the ends spun into the plies of the yarn) regardless of weight. So you could see a pattern, especially a vintage one, that calls for worsted wool meaning the type of wool not the weight.

All of the above terminology applies to yarn manufactured and sold for the US market. British terminology is totally different. In UK, Aus and NZ the weight of the yarn is defined by plies – nothing to do with the actual number of wraps. The symbols in the first chart are now being used on UK yarns but the wording is often as seen below.

0. Lace or 2 ply

1. 3,4 ply or jumper

2. 8 ply

3. DK is called DK

4. 10 ply or Aran

5. 13 ply