Knitting Needle Size Conversion Chart for US and Metric sizes.
| U.S. Size | Metric Size |
| 0 | 2.0 mm |
| 1 | 2.25 mm |
| 1.5 | 2.5 mm |
| 2 | 2.75 mm |
| 2.5 | 3.0 mm |
| 3 | 2.35 mm |
| 4 | 3.5 mm |
| 5 | 3.75 mm |
| 6 | 4.0 mm |
| 7 | 4.5 mm |
| 8 | 5.0 mm |
| 9 | 5.5 mm |
| 10 | 6.0 mm |
| 10 1/2 | 6.5 mm |
| 11 | 8.0 mm |
| 13 | 9.0 mm |
| 15 | 10.0 mm |
| 17 | 12.0 mm |
| 19 | 16.0 mm |
Standard Yarn Weight System
Source: Craft Yarn Council’s
https://www.craftyarncouncil.com/standards/yarn-weight-system
| Yarn Weight | Types of Yarn | Knit Gauge/Needle Size | Crochet Gauge Hook Size |
 | Lace Weight | 33-40 sts to 4″ on US 000-1 needles | 32-42 sts to 4″ on 6-8 steel or B-1 hook |
 | Sock, Fingering | 27-32 sts to 4″ on US 1-3 needles | 21-32 sts to 4″ on US B-1 to E-4 hooks |
| #2 | Sport, Baby Weight | 23-26 sts to 4″ on US 3-5 needles | 16-20 sts to 4″ on US E-4 to 7 hooks |
| #3 | DK, Light Worsted Weight | 21-24 sts to 4″ on US 5-7 needles | 12-17 sts to 4″ on US 7 to I-9 hooks |
| #4 | Worsted, Aran Weight | 16-20 sts to 4″ on US 7-9 needles | 11-14 sts to 4″ on US I-9 to K-10.5 hooks |
| #5 | Chunky, Bulky Weight | 12-15 sts to 4″ on US 9-11 needles | 8-11 sts to 4″ on US K-10.5 to M-13 hooks |
| #6 | Bulky, Roving Weight | 7-11 sts to 4″ on US 11-17 needles | 7-9 sts to 4″ on US M-13 to Q hooks |
| #7 | Jumbo, Roving Weight | 6 sts or less to 4″ on US 17-50 needles | 6 sts or less to 4″ on US Q and larger hooks |
Purchasing Needles
I am lucky to live close to Green Mountain Spinnery, Harrisville Designs, and WEBS for a great selection of knitting needles.
My favorite place to buy online needles is Jimmy Beans Wool. They offer many varieties of knitting needles with fast shipping and excellent service. They also have an Advanced Needles Search to find the perfect needle for your project!