When working with vintage knitting patterns, one of the first things you will notice is that the needles are often described very differently from the way they are today. Older British patterns commonly give needle sizes as numbers such as No. 8, No. 10 or No. 12, rather than in millimetres. American patterns may use a completely different numbering system, while modern British patterns generally give the actual diameter of the needle in millimetres.
This can be confusing at first, particularly because the old British and American numbering systems work in opposite directions.
The Old British Needle Sizes
The traditional British needle numbering system developed from the British Standard Wire Gauge (SWG) system. The numbers originally related to the thickness of wire used to manufacture needles, rather than being a direct measurement of the needle’s diameter. As a result, the numbering system is not linear.
Most importantly, the higher the old British number, the thinner the needle.
For example, an old British No. 10 needle is 3.25 mm, while a No. 4 is 6 mm.
This is the opposite of the American system, where a higher number generally means a thicker needle. This is why it is particularly important not to assume that a vintage British “No. 8” means the same thing as a US size 8.
British knitting gradually changed to metric needle sizes during the 1970s. Metric sizes were introduced during the middle of the decade, and by around 1977 needles were generally being sold with metric measurements rather than the old numbered system. (Metrication UK)
This means that many of the vintage patterns in this book were originally published using the old British needle numbers. I have converted these to modern millimetre sizes throughout the patterns to make them easier to use.
British Imperial to Metric to US Needle Sizes
The following list gives the most useful conversions when working with vintage British patterns.
Old British No. 14 = 2 mm = US 0
Old British No. 13 = 2.25 mm = US 1
Old British No. 12 = 2.75 mm = US 2
Old British No. 11 = 3 mm = US 2½
Old British No. 10 = 3.25 mm = US 3
Old British No. 9 = 3.75 mm = US 5
Old British No. 8 = 4 mm = US 6
Old British No. 7 = 4.5 mm = US 7
Old British No. 6 = 5 mm = US 8
Old British No. 5 = 5.5 mm = US 9
Old British No. 4 = 6 mm = US 10
Old British No. 3 = 6.5 mm = US 10½
Old British No. 2 = 7 mm
Old British No. 1 = 7.5 mm
Old British No. 0 = 8 mm = US 11
Old British No. 00 = 9 mm = US 13
Old British No. 000 = 10 mm = US 15
These conversions follow the traditional British-to-metric equivalents used for vintage patterns. Some intermediate sizes do not have a direct old British equivalent, which is why modern metric sizing includes measurements such as 2.5 mm, 3.5 mm and 12 mm. (Metrication UK)
The Most Important Thing to Remember
If you are ever unsure about a vintage needle size, look for the millimetre measurement rather than relying on the number alone.
For example:
A British No. 8 = 4 mm.
A US No. 8 = 5 mm.
They are not the same needle.
This difference is particularly important when using a vintage pattern from Britain alongside modern American knitting equipment or yarn. A mistake of even 1 mm can make a noticeable difference to the fabric produced.
For the patterns in this book, the original needle sizes have been converted into modern metric measurements wherever possible, so you can simply use the millimetre size stated in the pattern.
Vintage Needles and Tension
It is also worth remembering that the needle size given in a vintage pattern was chosen to work with the yarn available at the time. Vintage yarns could differ from modern yarns in thickness, twist, fibre composition and elasticity, so using exactly the same needle size does not necessarily guarantee exactly the same tension.
Where the original pattern gives a tension or finished measurement, these are useful guides. If your knitting is noticeably tighter or looser, you can change the needle size to achieve a fabric that you like.
The important thing is not to be intimidated by the old needle numbers. Once you know that a vintage British No. 8 means 4 mm, a No. 10 means 3.25 mm and a No. 4 means 6 mm, these patterns become much easier to understand.
The old terminology discussed in this article is simply another little piece of the history of knitting. Once translated into modern measurements, there is no reason why wonderful old knitting patterns cannot be enjoyed by knitters today.
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