Understanding Imperial Knitting Needle Sizes

Most knitters, whether beginner or experienced, will want to try out working from vintage knitting patterns at some point.

From classic vintage cardigans to fun 1980s character sweaters, vintage knitting patterns offer us the opportunity to create stunning, nostalgic garments.

Not only will our wardrobes really stand out from the crowd, we can also use vintage knitting patterns to bring back some wonderful memories.

Thanks to websites such as Etsy, vintage knitting patterns are really easy to source. Additionally, they are often sold as digital files which can be instantly downloaded.

Before knitting a vintage pattern, there a few things that you need to be clear about.

For example, the terms used for knitting needle sizes can differ considerably. You may also need to find a suitable yarn substitution.

Please read on to find out more.

This post may contain affiliate links.

Understanding Vintage Knitting Patterns

A vintage knitting pattern for pocket scarf, very fashionable at the moment.

Vintage knitting patterns are, on the whole, just as easy to understand as modern ones.

Before buying a vintage knitting pattern though you should understand that you may not be able to purchase the exact same yarn as stated in the pattern.

The best starting point to find a modern day substitute is to look at what knitting needles are called for in the pattern. I would then pull out said needles and knit a small swatch in some yarn that you have which matches the knitting needles.

You can then compare this swatch with the tension gauge given in the vintage knitting pattern and see how it compares.

It is then fairly easy to work out if you need a thicker or thinner yarn and you can start to look for a suitable substitution.

Of course, to do this it is very important that you use the correct size of knitting needles. The knitting pattern will tell you the size, but this in itself might not be as straight forward as you may think.

Please read on to discover more about vintage knitting needles.

Why Vintage Knitting Needle Sizes Can Be Confusing

An important issue with vintage knitting needles is that you need to know whether the pattern is US or UK in origin. That is because both US and vintage (imperial) UK knitting needle sizes are indicated with a number, rather than a mm size.

This can be really confusing. For example, number 6 can be either 5mm or 4mm knitting needles, depending on whether you are converting from a US or UK pattern. A number without a mm on a vintage UK pattern will be an imperial knitting needle and a number on a vintage US pattern will be a US size, which is the same as the modern day size.

An example of a very popular vintage knitting pattern which may cause knitting needle size confusion would be one of the awesome retro character sweaters for sale in this Etsy store.

Awesome vintage Sesame Street knitting pattern.

These extremely popular knitting patterns are all from the UK, and the needle sizes given are imperial (I know because I’ve been buying them!).

One would imagine that this may be confusing for knitters from the USA who may not realise that some vintage knitting patterns give these now non existent imperial knitting needle sizes. It would be easy to think that as no mm is indicated, that the needle sizes are simply US sizes.

I would recommend asking the sellers of vintage knitting patterns for the origin of the patterns, if you are at all confused.

Imperial/US/MM Knitting Needle Conversion Chart

Here is a conversion chart which will help you to work out which size knitting needles you will need to use when knitting a vintage knitting pattern.

As you will see, some of the imperial sizes don’t exist in US needle availability.


I hope this knitting needle conversion chart will help you, should you ever decide to give vintage knitting a try.

Vintage designs are just so beautiful that is really is worthwhile getting to grips with the patterns.

2 thoughts on “Understanding Imperial Knitting Needle Sizes

    1. You are very welcome! Yes I’ve printed this chart out ready for the next vintage project, I can never remember the sizes off by heart 🧶


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