Yarn weights......a quick reference:

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
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.