Sizing Vintage Patterns
One of the most important things to remember is never buy a vintage sewing pattern according to it's size number. Modern sizing and vintage sizing are two very different things. When buying a vintage pattern don't buy based on the size printed on the envelope...buy according to your measurements. Most of the patterns you will find on VintageStitching.com have all the measurements noted in the pattern description. This information is taken directly off the envelope.
There is a difference between how clothes are worn today as compared to how vintage clothing was worn. Most ladies today don't wear the foundation garments such as girdles or bras that give the perfect conical shape like in the 1950's or 1960's. Patterns from that era are fitted for ladies wearing those garments.
It is recommended to know your body measurements with and without foundation garments. Bust measurements can change with bra styles so it is important to know what will be worn underneath the finished vintage garment.
Over time, clothing companies have made the clothes bigger and the size numbers smaller. The best idea is to buy the size of pattern that will fit in the most difficult to fit area. This is usually the size that corresponds to bust measurement.
There are many websites on the internet that give detailed instructions on how to resize a vintage pattern if needed. Here is a good link that breaks it all down: