Needle & Hook Size Converter 📏
Convert knitting needle and crochet hook sizes between US, UK, and metric (mm) systems. Full reference chart with recommended yarn weight for each size.
How to Use the Needle Size Converter
Knitting needle and crochet hook sizes are labeled differently in the US, UK, and metric systems. This table provides a quick reference for all three.
US sizes use numbers (0–17 for needles). UK sizes use a reverse scale. Metric sizes are in millimeters and are the most universal system.
The recommended yarn weight column gives a general guideline. Always check the yarn label for the manufacturer's recommended needle size and swatch to confirm.
FAQ
Which needle size system is most universal?
The metric system (millimeters) is the most universal and precise. US and UK sizes are older systems with some inconsistencies between manufacturers. When in doubt, use the mm size to ensure you have the correct needle.
What needle size should I use for worsted weight yarn?
Worsted weight yarn typically uses US 7–9 (4.5–5.5mm) needles. However, always check the yarn label for the manufacturer's recommendation and swatch to confirm your gauge matches the pattern.
Are US and UK needle sizes the same?
No. US and UK needle sizes use different numbering systems and are not interchangeable. A US size 8 needle is 5mm, while a UK size 8 needle is 4mm. Always verify the mm size when converting between systems.
What is the difference between circular and straight needles?
Straight needles are used for flat knitting (back and forth). Circular needles can be used for both flat and in-the-round knitting. The needle diameter (mm) is the same regardless of needle type — only the length differs.
How do I choose between aluminum, bamboo, and plastic needles?
Aluminum needles are slippery and fast, good for smooth yarns. Bamboo needles have more grip, ideal for slippery yarns like silk or bamboo. Plastic needles are lightweight and flexible. Personal preference plays a big role — try different materials to find what works best for you.