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Knitting Needle Sizes – The Complete Guide & New Free Conversion Chart

When you’re a beginner, one of the most helpful and essential things to learn at the start of your journey is knowing about knitting needle sizes. This helps you choose the right needle for your project.

Don’t worry too much, it’s simple to understand, and my conversion charts are sure to help you.

For a more comprehensive look at everything on knitting needles, visit my post, My Complete Guide To Knitting Needles. All The Best Knitting Needle Types And When To Use Them here.

Knitting is a beautiful craft, and having this knowledge will make it easier to get straight on to the good stuff, knitting your project!

Table Of Contents

How Do I Know What Size Knitting Needles To Use?

If you’re working with a pattern, this can be a lifesaver as they will tell you the ones best to use, they recommend a size and the gauge you’re supposed to create with that.

Make a swatch first (about 4”) with your chosen yarn, wash it, and let it dry. Once it’s dry, if it’s too big, size down a needle. If it’s too small, do the opposite.

If you’re working with your own project, choose the yarn first, then the label will tell you which needles are best to use.

Knitting Needle Size Conversion Chart

Metric (mm)UKUSJapan
1.2516000
1.51500
1.75
21400
2.25131
31
3.251222
3.5113
3.751034
445
4.25955
4.5866
4.757
5778
5.259
5.56810
5.755911
612
6.2541013
6.514
6.75310 1/215
727
7.51
80118
900139
100001510
1217
1619
1935
2550
Based On Standards From The US Craft Council

Here is the guide in an image format, for an easy reference.

Knitting Needle Size Conversion Chart

A few essential things about knitting needle sizes. There are four sizes mentioned on this chart, Metric, UK, US, and Japan.

Metric is measured by how many millimeters are in the diameter of the needle.

UK sizing is measured in numbers getting smaller, the bigger the size of the needle. These range from 16-000

US sizing is measured in numbers getting bigger, the larger the size of the needle. These range from 000-50.

Japan sizing goes from 0-15 as the numbers get larger, but then once they’re past 15, it switches to metric sizing.

If you can’t find a direct equivalent in your sizing system, the best bet is to find the closest metric equivalent.

When you’re buying them, they’re usually listed in both metric and US, these are the most common sizing systems. Australia, Canada, and New Zealand use the metric sizing system.

A Rundown On What Sizes Are Best Suited For Which Projects

US Size 000-1

These are the smallest ones you can possibly find. Probably best to avoid these if you’re a beginner, get hand pain, or don’t have the patience!

These are designed for lace or projects with intricate designs, used with very fine yarn. They’re also quite challenging to get your hands on because they’re used for particular tasks.

US Size 1-3

Instantly recognizable as the most common one used for socks. Most sock yarn is specially designed for these ones, and once you learn to make them, well, making socks can become addictive!

(This is coming from someone who, at the time of writing, is on her fifth pair of socks!) In addition to this article of clothing, you can also make lovely open or lacy shawls.

US Size 3-5

Designed for use with the sport-weight yarn, or yarn weight category 2, these needles are still considered thin.

Some of the most versatile of all of these listed, you can make all sorts of things, from sweaters, cardigans, and clothes, to thicker socks, baby blankets, and intricate scarves.

Sometimes your hands may cramp when using these, have regular breaks and do hand exercises to prevent this from happening.

US Size 5-7

For use with DK weight yarn, (not to be confused with worsted weight, as that is slightly thicker than DK.) It’s widespread across all sorts of patterns for almost anything you could possibly think of.

US Size 7-9

By far the most common and popular size, if you’re a beginner, this is probably the size range you’ll start your knitting journey with.

If you’re familiar with knitting, this was perhaps the one you learned with! Used in conjunction with worsted weight yarn.

US Size 9-11

Chunky or bulky weight yarn is the best choice for this type of needle. (Quick tip, it’s best to use circular needles for these large projects, as the cable holds the weight and less strain on your hands.)

US Size 11-17

Designed for bulky yarn or when you want to knit up a chunky blanket, sweater, or similar winter garment, or you want something that will knit up very quickly. Excellent for cable knitting.

Note: Once you get past this size, there stops being even numbers in US sizing. Don’t bother looking for size 16 or 14, for example, because they don’t exist!

US Size 17 and Bigger

These are seriously large! For extreme knitting with jumbo yarn, (the newest addition to the yarn weight categories.)

Be warned though, they’re quite hard to manage and might feel very awkward at first, but with practice, it will become easier. Best to get plastic or light wood, they’re less cumbersome.

Your Questions Answered

What Is 3mm Knitting Needles In US Size?

A 3mm knitting needle doesn’t have a direct conversion to US size, but the closest are 15 or 14.

What Is The Biggest Knitting Needle Size?

Probably the biggest knitting needle size is US 50, or 25mm. These are seriously huge, for super, super chunky yarn!

What Size Is 9mm Knitting Needles?

9mm knitting needles are 13 In US Size, 00 in UK size, and 9mm also in Japan.

What Size Are 12mm Knitting Needles?

12mm knitting needles are 17 in US size and have no direct equivalent in the UK or Japan size.

What Size Is Us 10.5 Knitting Needles In UK?

US 10.5 in UK size is 3.

What Size Is A 3.75 Knitting Needle?

A 3.75mm knitting needle is 10 in the UK, 3 in US size, and 4 in Japan.

Keep this post bookmarked for whenever you need a handy reference, or feel free to download the image to keep whenever you need it, even when you’re offline.

I hope this is helpful for you, and feel free to share this with other knitting friends who may benefit from this resource.

About Jodie Morgan

Hi. I’m Jodie Morgan, owner and creator of Knit Like Granny. (Yes, I’m a real person :) ) Thanks for being here.

I created Knit Like Granny to help show 1,000,000 people the benefits of knitting & highlight alternatives to fast fashion.

I love knitting and have met so many other fabulous knitters through this site. I enjoy learning and helping others discover the joys of working with yarn.

Please say hello!

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