Knitting Needle Size Converter
Convert needle sizes between US, metric (mm), and UK/Canadian systems.
Quick Converter
Full Conversion Reference Table
| US Size | Metric (mm) | UK / Canadian |
|---|
Metric-Only Sizes (No US Equivalent)
| Metric (mm) | Notes |
|---|---|
| 2.5 mm | Between US 1 and 2; common in European patterns |
| 3.0 mm | Between US 2 and 3; common in European patterns |
| 3.5 mm (US 4) | Also listed as metric 3.5 in some EU patterns |
| 4.5 mm | Between US 7 and 8; used in some European patterns |
| 5.5 mm | Between US 9 and 10; common in some EU designs |
| 7.0 mm | Between US 10.5 and 11 |
| 11.0 mm | Between US 15 and 17 |
| 13.0 mm | Between US 17 and 19 |
How to Use This Converter
- Use the Quick Converter — choose a size system and select a needle size to see all equivalents instantly.
- Use the search box above the table to filter by US number, mm size, or UK number.
- Note that some US sizes share the same metric size (e.g., US 4 and US 5 are both close to 3.5–3.75mm).
Understanding Needle Size Systems
- US: Numbered 0–50. Larger numbers = larger needles.
- Metric (mm): Measures actual shaft diameter. The most accurate and internationally consistent system.
- UK/Canadian (old system): Numbered in reverse — higher numbers = smaller needles. This system is largely obsolete but still appears in vintage patterns.
- When in doubt, always use the mm measurement to match your needle correctly.