Knitting Needle Size Chart: US vs UK vs Metric
Knitting needle sizes vary across countries and manufacturers. The US uses a numbered system (0-50), the UK uses an inverted numbered system (14 down to 000), and the metric system measures the actual diameter in millimeters. Metric is the most reliable because it describes the physical needle — a 5mm needle is always 5mm regardless of brand.
US vs UK Needle Size Differences
| Feature | US System | UK System |
|---|---|---|
| Numbering | 0 to 50 (ascending) | 14 to 000 (descending) |
| Larger number means | Larger needle | Smaller needle |
| Most common range | US 1-15 | UK 14-000 |
| Used in | North America | UK, Australia, some EU |
| Precision | Has half sizes (e.g. 2.5, 10.5) | Whole numbers only |
Which Needle Size for Which Yarn?
| Yarn Weight | Needle (mm) | Needle (US) | Gauge (st/4in) |
|---|---|---|---|
| Lace (#0) | 2.0-2.25 | 0-1 | 32-40 |
| Fingering (#1) | 2.25-3.25 | 1-3 | 28-32 |
| Sport (#2) | 3.25-3.75 | 3-5 | 24-26 |
| DK (#3) | 3.75-4.5 | 5-7 | 21-24 |
| Worsted (#4) | 4.5-5.5 | 7-9 | 16-20 |
| Bulky (#5) | 5.5-8.0 | 9-11 | 12-15 |
| Super Bulky (#6) | 8.0-12.0 | 11-17 | 7-11 |
| Jumbo (#7) | 12.0-25.0 | 17-50 | 1-7 |
FAQ
Why do US and UK sizes go in opposite directions?
The UK system developed first using standard wire gauge numbers, where higher numbers mean thinner wire. The US system was created later and sensibly counts up as needles get bigger. This is why UK 14 is tiny (2mm) while US 14 is not a standard size — it would fall between US 13 and US 15, roughly 9.5mm.
My pattern says "4mm needles" — which US size?
A 4mm needle is US 6. When patterns specify millimeters, that is the most precise measurement. Use our converter above to find the exact US or UK equivalent.
What if I am between sizes?
Always knit a gauge swatch. If your gauge is too tight (too many stitches per inch), go up one needle size. If too loose (too few stitches), go down one size. The needle size on the yarn label is a starting point, not a rule.
Related Tools
- Crochet Hook Size Converter — US, UK, and metric hook sizes
- Knitting Gauge Calculator — measure your swatch with the right needles
- Yarn Weight Converter — match yarn weight to needle size
- Knitting Stitch Calculator — cast-on stitches from gauge