Knitting Needle Conversion Chart

 Knitting Needle Conversion Chart 

by Janice Jones |Updated 10-15-2023

Beyond shopping for yarn, the next best thing about knitting is picking out the right knitting needles for the job.

The options for knitting needles have increased exponentially in the 21st century, so hopefully you have purchased a BIG knitting bag as you’ll likely eventually fill it to the brim.

Shades of blue and green yarn with a pair of straight knitting needlesKnitting Needle Conversion Chart

The types, sizes, shapes, and materials used to make them are almost as varied as the yarns available today.  There is also plenty of opinionated knitters out there claiming that one needle is better than another. 

They are right in a sense, there are knitting needles that are right for them, but that doesn’t mean they will be right for you.  Each person approaches knitting a little differently so a one size fits all doesn’t apply here.

Let’s face you, you’ve probably have been bitten by the knitting bug because you love the thought of a hand-made finished project.  But along the way, the sheer act of knitting becomes as important than the finished project.

Knitting Needle Conversion Chart

I’m going to go through all the different types of needles and then help you decide where you’d like to spend your money.  Remember, this is not an expensive hobby starting out and even very inexpensive needles will last a very long time, so don’t be tempted to purchase the most expensive needles unless that is what you want to do.

Before I mention all the different types of needles you can purchase, you might like to know that sizing does matter and can be a bit confusing.  So Keep reading if you'd like more general information about needles or click here to get to the knitting needle conversion chart.

Straight Verses Circular Knitting Needles

While there are a variety of different types of needles, most can be divided into one of two categories:  Straight or Circular.

Straight Needles

Knitting needles and yarnStraight Needles Made of Bamboo

Straight needles are used for flat knitting where each flat piece of knitted fabric can be sewn together to create a finished project.  Straight needles can be pointed on one end or double pointed with points on either side. 

Straight Double Pointed Needles

Set of double-pointed knitting needlesStraight Double Pointed Knitting Needles

Those that are double pointed are normally smaller and are used for smaller projects that are worked in the round such as socks. 

Needles also come in different sizes depending on the project at hand. Straight needles are still the most popular for most beginner level projects

Circular Needles

One circular knitting NeedleCircular Knitting Needle

Circular needles have the normal pointed needle tips but are connected to one another by lengths of smooth plastic or nylon or plastic cord. 

Not only are they sold by the size of the needle tips, but also by the length of the plastic cord that connects them.  Circular needles are intended to working in the round, but they can also be used to work flat projects simply by turning your work at the end of the row. 

Since the needle portion is much smaller than with straight needles, circular needles fit easily in knitting bags and are more portable when knitting on the go.  Another option for circular needles is the interchangeable needle.

Here are two sets of circular needles worth checking out on Amazon

The kit includes 6 needles - Size 13 10 8 6 4 0. Each needle tip is 4.5" long. The tube is 7" long. Total length is 16" long, nice for small knit projects

The kit includes 6 pairs - Size 15, 11, 9, 7, 5, 2. Each needle tip is 5.75" long. The tube is 28" long. Total length is 40" long, nice for bigger knit projects

Interchangeable Needles

These are purchased in sets that come with various sizes of needle points that can be attached to different sizes of plastic cording.  They represent a more substantial investment initially; they can actually save you money in the long run especially if you think you will be using circular needles for a variety of projects.  The best part of purchasing a complete or starter set of circular needles in this way is that they normally come in their own case that help you organize and keep tract of the different sizes.  

Whether you decide to purchase circular needles individually or as an interchangeable set, look for ones that have a smooth transition between the needle points and the plastic or nylon cord that connects them.  Rough connections can cause your yarn to split or get snagged making knitting more difficult.

Interchangeable Needles Made from Wood

I love this set because it's not only beautiful, but has the most popular sizes that will help you create a wide variety of projects. 

The set 

includes 9 pairs of 4.75" long interchangeable wood needle tips in US sizes 4-11 (3.5mm - 8mm), 4 purple cables (2 each in 24" and 32" lengths), 8 purple end caps and 2 metal tightening keys

Cable Needles

I know that I mentioned that there are only two types of needles (straight or circular) but there is actually a third type of needle worth mentioning. 

Cable needles are required if you plan to make the cable stitch for say a hat, scarf or sweater.  They are short, double pointed needles that have a bend in the middle.  That bend or grove in the center helps keep stitches from falling off as it holds the cable stitches in place.

Check out the variety of cable needles on Amazon

Needle Sizes:  U.S, U.K., Metric:  Knitting Needle Conversion Chart

Whether you are speaking about circular or straight needles, all come in a standard range of sizes.  The size depends on the diameter of the needle and is expressed as a number or a metric number.  Here ends the similarity.  This is where the knitting needle conversion chart comes into play.

U.S. Verses Metric

Needles manufactured or marketed for the US are tagged with U.S. sizing.  In the U.S. needles are sized from 0 to 50 with the diameter of the needle increases with the size.  So for example a U.S. needle size of 5 would be much smaller than the U.S. Number 10 needle.

Outside of the U.S., needles are sized according to the metric scale and measurements are in millimeters.  The diameter of the needle is used to determine the size, so the smaller the number the smaller the needle.

Old British Sizing

Once popular, the UK sizing is just the opposite as present-day sizing.  In this system, the smaller the number, the larger the needle and vice versa. 

In my own experience, I tend to use the US sizes of 6 (4 mm) to 10 (6 mm) more frequently than any other needles but I do keep larger and smaller needles should I decide to pick up a project that requires a smaller or larger needle.

Which Size to Use

When you purchase a skein, hank or ball or yarn, the label should tell you approximately which size needle to use.  This information, however is not written in stone and will depend on how you knit. 

Each knitter has a slightly different tension to her/his work and depending on how loose or how tight you make your stitches will determine your gauge.  Ideally, you will want to choose the needle that helps you match the gauge on the pattern you want to use.

Knitting Needle Conversion Chart

Metric to U.S to U.K

Millimeters                          U.S. Size               U.K Sizes

2.00 mm                              0                             14

2.25 mm                              1                             13

2.75 mm                              2                             12

3.25 mm                              3                             10

3.5 mm                                 4                             -             

3.75 mm                              5                             9

4 mm                                    6                             8

4.5 mm                                 7                             7

5.0 mm                                 8                             6

5.5 mm                                 9                             5

6 mm                                    10                           4

6.5                                         10 ½                       3

7 mm                                    -                              2

7.5 mm                                 -                              1

8 mm                                    11                           0

9 mm                                    13                           00

10 mm                                  15                           000

12.75 mm                           17                           -

15 mm                                  19                           -

19 mm                                  35                           -

20 mm                                  36                           -

25 mm                                  50                           -

Would you like to download a printable Knitting Needle Conversion Chart to keep in your knitting bag?  Don't worry, it's free.

Needle Lengths

Needle lengths are actually a matter of personal preferences.  For me, I prefer to choose a needle length that matches my project.  If I’m making the back of a sweater, I want a longer needle that will hold all of the stitches.  But that long needle might get in the way if all I want to do is make a quick swatch to measure gauge. 

In the U.S., the length of the needle is given in inches but in the rest of the world, it is provided in centimeters.  For straight needles, the common sizes are 10 inches (25 cm) and 14 inches (36 cm).  Double pointed needles are generally a little bit shorter (4 inches to 10 inches or 10 to 25 cm).

Circular needles range from 16 to 40 inches (40 to 102 cm)

Materials Used in Knitting Needles

There are a variety of different types of materials used for making knitting needles.  The most common today include metal, plastic, and bamboo.  But you might also find needles made from wood, casein, carbon fiber composite or glass.

Metal Needles

The most common types of metal needles include aluminum, stainless steel, nickel, and nickel plate.  The larger needles will likely have a hollow core, making them less heavy and easier to use.  Metal needles are smooth, slippery and cool to the touch. 

Stitches slide easily on these surfaces and make knitting faster.  Aluminum made needles are the least expensive and may bend over time or scratch. Stainless-steel-, nickel, and nickel-plated needles are more expensive but are virtually indestructible.

This set of Metal Straight Needles from Amazon Includes

This set includes 14 pairs with sizes 2mm to 10 mm.  The length is 13.8 inches or 35 cm long. 

Plastic Needles

Many jumbo-sized needles are made of plastic because they are light weight and come as either hollow or solid with the larger needles being hollow.  They are not as smooth as metal but smoother than wood or bamboo, stitches can still slide. 

Warmer than metal, they may be more comfortable for some with cold hands or those suffering from arthritis. Plastic needles do have their down side as they can warp and even break over time.


Many web knitters love the bamboo needles because they are strong, flexible and lightweight.  They are more affordable than wood and are a popular eco-friendly alternative. 

They are smooth but nearly as slick as the metal or plastic needles, they do make a good choice for beginners because stitches don’t slide off as easily.  This characteristic does make knitting a slower process, but for those just starting to knit, they may be the ideal choice.


There is a wide range of wood needles from factory made to intricately carved hand made needles.  They can become the most expensive type of needle and top of the line. 

A set of ebony needles is the hardest and top of the line with the rosewood, a close second.  Other wood needles include birch, maple, walnut, cherry and coconut palm.


Casein needles are completely biodegradable, flexible and light weight.  They are warm to the touch and they can be colored in many different ways.  They have a smooth surface but not as slippery as metal.  Heat can damage them so don’t leave them in a hot car or near a radiator.

Carbon-fiber Composite

These needles are made from a polymer composite reinforced with carbon fiber.  They’re strong and lightweight and are often used for making very small needles (1.25 mm).


Glass needles have a smooth surface ideal for fast knitting and are strong and warm.  There is no flexibility with these needles.  They are more likely to break so require more care.

Not sure what size your needles are?

You may need a needle gauge.

Needles and gaugeNeedle Gauge

Most straight needles are marked with the needle size, but straight double ended ones do not.  Most circular needles are also not marked, so unless you place them in a clearly marked case, you may not remember which size they are when you go back to use them again. 

Use the needle gauge by inserting the tip of the needle into the hole.  If the needle can be placed comfortably in a specific hole, then that is the size of your need.  If it fits too loosely, place it in the next smaller hole.

Pin for Future Reference:  Knitting Needle Conversion Chart

Knitting needles and yarnKnitting Needle Conversion Chart

Did you find this information on knitting needle conversion char helpful?  Then, you might like these too.

About Janice

Hi, I’m Janice, the voice behind Smart-Knit-Crocheting. I love to knit and crochet and even more, I love teaching others what I know.

Though I learned to knit and crochet as a child, I didn’t get serious about these amazing hobbies until I retired. I’m a certified knit and crochet instructor through the Craft Yarn Council and am working on becoming a Master Hand Knitter through The Knitting Guild Association.

I’m currently living with my husband of over 50 years and our 7 Shih Tzu dogs.

I love hearing from you, so please drop me a line and let me know what you’re working on, whether you love knitting or crocheting more, and if you have any questions. Please visit my about me page for more information.

Happy Crocheting