Online Tool Store
Knitting Needle Size Converter
Knitting Needle Size Converter reads the number on the needle; your gauge swatch is what decides whether that size is right for the pattern.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Unit & Converters
Knitting Needle Size Converter
Frontend preview — no upload or external service.
Needle size
4.5 mm is US 7 and UK 7. Note that UK sizes run in the opposite direction to US — UK numbers get smaller as the needle gets thicker.
How the Knitting Needle Size Converter works
- Enter the size printed on the needle, or measure the shaft with a needle gauge if it has worn off.
- Choose the system it is written in and the system you need.
- Check whether the conversion is exact or the nearest available size — several US sizes have no exact metric twin.
FAQ
Why do UK and US sizes run in opposite directions?
US sizing numbers increase with needle diameter; the older UK and Canadian system numbers decrease. A UK 7 and a US 7 happen to coincide at 4.5 mm, which causes a lot of confusion.
Are conversions exact?
Not always. Some traditional US and UK sizes fall between metric sizes, so the chart gives the nearest available needle. Since gauge depends on the exact diameter, a rounded conversion may change your tension.
Does needle material affect gauge?
Yes. Slippery metal needles usually produce looser stitches than wood or bamboo at the same nominal size, which is one more reason to swatch rather than trust the size marking.
How we compare
| Feature | Online Tool Store | A search-engine answer box | A reference table |
|---|---|---|---|
| All three systems | ✓ | Two | ✓ |
| Flags inexact conversions | ✓ | ✗ | ✗ |
| Works offline once loaded | ✓ | ✗ | Printed chart |
| No install | ✓ | ✓ | ✗ |
Knitting Needle Size Converter reads the number on the needle; your gauge swatch is what decides whether that size is right for the pattern.