Knitting Needle Size Conversion Chart
Knitting needle sizing differs between the UK, US and metric systems. Older UK patterns use the traditional British sizing (where a higher number means a thinner needle), while modern patterns almost always use metric (mm). This chart covers every common size to help you follow patterns from any era or country.
Full Needle Size Conversion Table
| Metric (mm) | UK Old Size | US Size | Typical Yarn Weight |
|---|---|---|---|
| 2.0 | 14 | 0 | Lace / 2 ply |
| 2.25 | 13 | 1 | Lace / 3 ply |
| 2.75 | 12 | 2 | 3 ply / 4 ply |
| 3.0 | 11 | — | 4 ply |
| 3.25 | 10 | 3 | 4 ply |
| 3.5 | — | 4 | 4 ply / DK |
| 3.75 | 9 | 5 | DK |
| 4.0 | 8 | 6 | DK |
| 4.5 | 7 | 7 | DK / Aran |
| 5.0 | 6 | 8 | Aran |
| 5.5 | 5 | 9 | Aran / Chunky |
| 6.0 | 4 | 10 | Chunky |
| 6.5 | 3 | 10½ | Chunky |
| 7.0 | 2 | — | Chunky |
| 7.5 | 1 | — | Chunky |
| 8.0 | 0 | 11 | Super Chunky |
| 9.0 | 00 | 13 | Super Chunky |
| 10.0 | 000 | 15 | Super Chunky |
| 12.0 | — | 17 | Jumbo |
| 15.0 | — | 19 | Jumbo |
| 19.0 | — | 35 | Jumbo |
| 25.0 | — | 50 | Jumbo / Arm knitting |
The old UK sizing system is no longer used in modern patterns but appears frequently in vintage and charity shop pattern leaflets.
Find Your Ideal Needle Size
Use our calculator to determine the best needle size based on your yarn and desired gauge:
- Needle Size Calculator — find the right needle size for your yarn and tension
Needle sizes are standardised to ISO 6715. Some US sizes have no exact UK equivalent and vice versa. When in doubt, use the metric (mm) measurement — it is the most precise and universally understood system.