Knitting Needle Sizes: An international size conversion chart
Have you ever been confused by the different knitting needle size conventions? There are three main ones: metric, US, and Imperial. It can be hard to keep track of which one is which, especially if you're new to knitting, which is why we’ve put together the below chart to keep you right.
A brief history of knitting needle sizes
Knitting has been around for centuries, and the different needle size conventions have evolved over time. The metric system is the most recent convention, and it's the one that's most widely used today. It is based on the diameter of the needle in millimeters. For example, a 4mm knitting needle is 4 millimeters in diameter.
The US convention is the second most widely used knitting needle size convention.The US sizing system is based on the number of stitches per inch that can be knit on a given needle size. For example, a size 6 needle is used to knit 6 stitches per inch. This system is simple and easy to understand, but it's not as precise as the metric system.
The UK convention is still used in the UK today, but it's becoming less and less common. It is similar to the US convention, but the numbers run in the opposite direction. For example, a UK size 10 knitting needle is 3.5mm in diameter, while a US size 10 is 7mm in diameter.
Needle Sizes
| Metric
UK/Europe (mm) |
USA | Imperial
Old UK/ Canada |
|---|---|---|
| 2 | 0 | 14 |
| 2.25 | 1 | 13 |
| 3 | 2 | 12 |
| 3.25 | - | 11 |
| 3.5 | 3 | 10 |
| 3.75 | - | - |
| 4 | 4 | 9 |
| 4.5 | 5 | 8 |
| 5 | 6 | 7 |
| 5.5 | 7 | 6 |
| 6 | 8 | 5 |
| 6.5 | 9 | 4 |
| 7 | 10 | 3 |
| 7.5 | 10 1/2 | 2 |
| 8 | - | 1 |
| 8.5 | 11 | 0 |
| 9 | 13 | 00 |
| 10 | 15 | 000 |
| 12 | 17 | - |
| 15 | - | - |
| 16 | 19 | - |
| 19 | 35 | - |
| 20 | 36 | - |
| 25 | 50 | - |
These conversions are approximate.
Tracey is an accredited Knitting For All teacher based in Kintore, Aberdeenshire. When she’s not running classes or workshops locally, she’s out running trails or spinning yarn.
She’s been crafting for over 40 years. Crafting runs in the family, having learnt from her mum and grandma. Learning new crafts and passing on that knowledge is her mission. If it’s fibre related, she’ll most likely have tried her hand at it. She’s passionate about preserving crafts for future generations. She enjoys teaching the following: knitting, crocheting, weaving, nålbinding, and macramé, but this list is not exhaustive.
She believes crafting is beneficial for both our mental health and physical well-being, so it brings her great joy to share her love of the fibre arts with a wider audience.