Yarn Standards
http://www.yarnstandards.com/weight.html

Yarn Weight Symbol
& Category Names
lace super fine fine light medium bulky super bulky
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
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
Recommended
Hook in Metric
Size Range
Steel***
1.6–1.4
mm		 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
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
and
larger

* GUIDELINES ONLY: The above reflect the most commonly used gauges and needle or hook sizes for specific yarn categories.
** Lace weight yarns are usually knitted or crocheted on larger needles and hooks to create lacy, openwork patterns. Accordingly, a gauge range is difficult to determine. Always follow the gauge stated in your pattern.
*** Steel crochet hooks are sized differently from regular hooks--the higher the number, the smaller the hook, which is the reverse of regular hook sizing