Knitting Needle Size Conversion: US, UK, Metric & Japanese Sizes Explained

Understanding Knitting Needle Sizes: A Complete Conversion Guide

Knitting needle sizes can be confusing, especially when patterns use different sizing systems. This guide will help you convert between US, UK, metric, and even Japanese knitting needle sizes, ensuring you always have the right tools for your project.

Why Knitting Needle Sizes Vary

Different countries developed their own numbering systems for knitting needles. This means a US size 6 needle is not the same as a UK size 6 needle! Knowing how to convert between these systems is essential for successful knitting.

Knitting Needle Size Conversion Charts

Here are some helpful conversion charts to reference. These charts cover the most common knitting needle sizes across different systems.

Metric (mm)	US Size	UK Size
2.0 mm	0	14
2.25 mm	1	13
2.75 mm	2	12
3.0 mm	–	11
3.25 mm	3	10
3.5 mm	4	–
3.75 mm	5	9
4.0 mm	6	8
4.5 mm	7	7
5.0 mm	8	6
5.5 mm	9	5
6.0 mm	10	4
6.5 mm	10.5	3
7.0 mm	–	2
7.5 mm	–	1
8.0 mm	11	0
9.0 mm	13	00
10.0 mm	15	000
12.0 mm	17	–
16.0 mm	19	–
19.0 mm	35	–
25.0 mm	50	–

Understanding US, UK, and Metric Sizes

US Sizes

In the United States, knitting needle sizes are represented by numbers ranging from 0 to 50. Larger numbers indicate larger needles. This system is relatively straightforward, but it’s crucial to remember that it doesn’t directly correlate to metric measurements.

UK Sizes

The UK system uses numbers that decrease as the needle size increases. Sizes range from 14 (the smallest) to 000 (the largest). This can be counterintuitive, so always double-check your conversions.

Metric Sizes

Metric sizes, measured in millimeters (mm), are the most precise and universally understood. Most patterns now include metric sizes, making conversions easier.

Japanese Knitting Needle Sizes

Japanese knitting needles use a unique numbering system. Here’s a quick conversion chart:

Metric (mm)	Japanese Size
2.1 mm	0
2.4 mm	1
2.7 mm	2
3.0 mm	3
3.3 mm	4
3.6 mm	5
3.9 mm	6
4.2 mm	7
4.5 mm	8
4.8 mm	9
5.1 mm	10
5.4 mm	11
5.7 mm	12
6.0 mm	13
6.3 mm	14
6.6 mm	15

How to Measure Knitting Needle Size

If you have unidentified knitting needles, a knitting needle gauge is your best friend. These gauges have precisely sized holes that allow you to determine the needle size accurately.

Here’s how to use a knitting needle gauge:

1. Select a hole that looks close to the needle’s size.
2. Insert the needle into the hole.
3. If the needle fits snugly, that’s the correct size. If it’s too loose or doesn’t fit, try a different hole.

Tips for Accurate Conversions

• Always double-check: Before starting a project, confirm your needle size conversions using multiple charts.
• Consider yarn weight: The recommended needle size often depends on the yarn weight. Refer to your yarn label for guidance.
• Knit a gauge swatch: Even with the correct needle size, your gauge might differ. Knitting a gauge swatch ensures your finished project matches the pattern’s dimensions.

What to Do If You Don’t Have the Exact Size

If you can’t find the exact needle size specified in your pattern, don’t panic! You can often substitute with a needle that’s slightly larger or smaller. Just remember to knit a gauge swatch to ensure your project turns out as expected.

Sometimes, a slight variation in needle size can even enhance the fabric’s drape or texture. Experiment and see what works best for your project!