Vintage sizes such as 'WMS', 'WMNS', 'WX', 'OS' and 'XOS' can be difficult to understand these days and the actual sizes varied quite a bit between manufacturers. A vintage sizing comparison chart like the one below can only give approximate guidance. Therefore my advice would be to use this vintage system of clothing sizing as a very rough guide only and use the actual measurements of each garment instead - only that way can you be absolutely sure of accuracy.
I have compiled the following explanation of the meaning of each size, which I hope you find useful.
Fact: sizes WMS and WMNS were often shown with an apostrophe , for example WM'S and WMN'S. Both refer to the word 'women's' of course. Sometimes, WMS and WMNS standard size were described simply as Women's in advertising.
On 19 July 1946, the UK Board of Trade made a ruling that from that date all women's underwear sizes will be marked by numbers instead of letters in the hope that label sizes would be clearer and easier to understand. The letters OS and WX could still be used on 'outsize' ladies underwear provided they were accompanied by numbers as well. This ruling is important to anyone who wants to date vintage women's underwear because use of the old 'WMS', 'WX', 'OS' etc Alpha system would be manufactured no later than 1946. A little word of warning is due at this point though because I have seen clothing advertisements showing the old Alpha system as late as 1949, 1950 and even 1966, which strongly suggests manufacturers and retailers were reluctant to change for fear of confusion in the eyes of consumers.
Acceptance of the 1946 change over to a numerical system of clothing sizing was definitely slow for the female British consumer. Four years later in 1950, a member of the Drapers' Chamber of Trade Executive Council is on record as saying "The public do today as they have always done. They go around asking for W, SW and WX sizes. That is what they understand, and they don't want anything else". In 1953, the British Standards Institution were still trying to get over 30 clothing industry organisations to decide on a common numerical system of sizing, as had already been done successfully in America. Agreement on a standardised numerical sizing system in the UK was finally reached in 1954.
British made garments displaying the same size regularly had a margin of error of up to 2 inches until 1951 when the BS1445 standard was introduced in order to inspire trust and confidence in sizing for shoppers.
One of the reasons this archaic and confusing system of sizing clothing was eventually discontinued was that women with a fuller figure understandably resented being described as "extra outsize" (XOS) or "outsize" (OS) when buying clothes in shops.
To make matters even more confusing still there was a similar but different system in use in mid-century Australia that appears to be finer than the British system and used terms such as XSSW, SSW, SW, W, SOS, OS and XOS.
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This article was written by Emma Benitez, BA (Hons) in Fashion & Dress History, incurable vintage fashionista and the lady behind Nylon Nostalgia.
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As a seller of 1940s style vintage clothing I often see size labels with confusing terms such as 'W', 'WX', 'WMS' or 'OS'. While this old sizing method has now almost completely disappeared from use, anyone who collects and wears vintage garments will no doubt be puzzled by the old Alpha system of clothing sizes. In this helpful article I will share with you the meaning of sizes such as 'OS', 'WX' and 'WMS', based on my own experience of understanding old vintage labels. I hope you find this information useful.
When did the old vintage label sizes like WMS, WX and OS come to an end? On 19 July 1946 all British made ladies underwear had to use a new number system of sizing rather than the confusing W, WMS, WX, OS sizes.
Vintage British clothing labels like this one are typical of this method of sizing. In this case the CC41 garment label shows the single letter 'W', which is the same as 'WMS' or 'Women's Standard' size - in other words, approximately 'Medium' as we would know it in the present day. Once you know what size W is on your vintage label then identification of 40s style fashion becomes a lot easier.
Even back in the 1960's, the WMS, WX, OS vintage clothing sizing system was being described as "mysterious", as can be seen in this 1966 newspaper article. It seems that even in those days, this confusing labeling system was proving unpopular with consumers.
Even earlier still, as this 1958 British newspaper article points out, the "older" "SW, W and WX" system was adding to the confusion of shoppers as various clothing manufacturers used different sizing systems. This suggests me that this original Alpha system of labeling dates to the earlier 1950's and 1940's at least.
"It would be nice if stores and the people who make women's clothes could get to
Going back further still, to 1942, this newspaper article outlines further changes to the wartime CC41 Utility Mark clothing regulations abandoning the established SW, WMS, WX, etc. sizing system for a new one using letters of the alphabet - a true 'Alpha' system. As to some small extent the old WMS, OS etc. label system is still used today, I wonder if these proposals were ever really enforced.
A British newspaper ad from 1958 showing vintage sizes like WMS, WX and OS.