Free Crochet Craft Tools & Calculators
Interactive calculators, row counters, size converters, and planning tools engineered specifically for yarn crafters. 100% offline-ready.
Needle Size Converter
Knitting Needle Size Converter
Instant lookup between Metric (mm), US Numbers, and UK/Canadian gauge sizes.
5.0 mm
US Needle Size
US 8
UK / Canadian Size
6
Recommended for: #4 Worsted
Knitting Needle Size Conversion Chart — Metric mm, US & UK Measurements
Cross-reference metric millimeter diameters with US numbers, UK wire gauge sizes, and recommended yarn weights.
Knitting Needle Size Conversion Chart - Metric mm, US & UK Sizes
Knitting needle numbering systems vary significantly between North America, the UK, and continental Europe. Use our knitting needle converter to translate straight, circular, and double-pointed needle (DPN) sizes accurately.
Knitting Needle Size Comparison Chart
| Metric Diameter (mm) | US Size Number | UK / Canadian Size | Recommended Yarn Weight |
|---|---|---|---|
| 2.00 mm | 0 | 14 | #0 Lace |
| 2.25 mm | 1 | 13 | #1 Sock / Fingering |
| 2.75 mm | 2 | 12 | #1 Fingering |
| 3.25 mm | 3 | 10 | #2 Sport |
| 3.50 mm | 4 | — | #2 Sport / #3 DK |
| 3.75 mm | 5 | 9 | #3 Light / DK |
| 4.00 mm | 6 | 8 | #3 Light / DK |
| 4.50 mm | 7 | 7 | #4 Medium / Worsted |
| 5.00 mm | 8 | 6 | #4 Medium / Worsted |
| 5.50 mm | 9 | 5 | #4 Worsted / Aran |
| 6.00 mm | 10 | 4 | #5 Bulky |
| 6.50 mm | 10.5 | 3 | #5 Bulky |
| 8.00 mm | 11 | 0 | #5 Bulky / #6 Super Bulky |
| 9.00 mm | 13 | 00 | #6 Super Bulky |
| 10.00 mm | 15 | 000 | #6 Super Bulky |
Frequently Asked Questions
Q: What size is a US 8 in millimeters?
A: A US 8 knitting needle is exactly 5.0 mm, recommended for medium worsted weight yarn.
Q: Why do UK needle numbers count backwards?
A: Historical UK needle sizes are based on wire gauge standards where thicker wire had a smaller number (e.g. Size 14 is very thin 2.0mm, Size 0 is thick 8.0mm).