The fastest way to be disappointed by a vintage purchase is to buy your usual size. A size on a garment is not a property of the garment. It is a shorthand for a set of body measurements, as understood by the manufacturer, in the market it was made for, in the year it was made. Every part of that has changed since.
Sizing has drifted, mostly outwards
Across the twentieth century and into this one, the measurements attached to a given size number have generally grown. The garment labelled a particular size several decades ago was cut for a smaller body than the garment labelled the same size today. This is usually called vanity sizing, though it is really a mix of changing body measurements, changing target markets and competitive pressure on brands to let customers take a smaller number.
The practical consequence is simple: if you wear a modern size in a shop, expect an older garment with the same number to be smaller. How much smaller varies by decade, by country and by manufacturer, which is why any single conversion rule will fail you eventually.
The shape has changed too, not just the scale
Even where the measurements line up, the proportions may not. A garment cut in an earlier period is built for a different posture and a different silhouette.
- Shoulders were often narrower, and the shoulder seam sat closer to the neck.
- Rises were higher on trousers and skirts, sitting at or above the natural waist.
- Armholes were smaller and higher, which restricts movement but looks cleaner.
- Sleeve heads and sleeves were cut narrower, with more taper to a fitted cuff.
- Hems were longer on skirts and dresses, and far deeper on suits and coats.
- Waist suppression was stronger: a jacket built for one era may be sharply waisted where a modern jacket hangs straight.
This is why a vintage garment can measure correctly across the chest and still look wrong on you. The measurements are the starting point; the shape is what decides whether it works.
Old garments also shrink
A garment made decades ago has been washed and dried many times, and natural fibres shrink with heat and agitation. Wool knits and cotton shirts that were once the size on their label can be a size smaller now. Hand-washed and line-dried garments generally hold their measurements much better than anything that has been through a hot machine cycle repeatedly.
So the label tells you what a garment was, measurements tell you what it is now, and only the second is useful for buying.
Measure the garment, not yourself
The workable method for vintage is the reference garment method. Take a garment you already own that fits the way you want, lay it flat, and measure it. Those numbers are your target.
Then measure the candidate garment the same way, flat, without stretching it. The measurements that matter most:
- Chest or bust: pit to pit, laid flat. If a seller gives you a single “chest” number, ask whether it is the flat measurement or doubled — the two differ by a factor of two.
- Waist: across the narrowest point, laid flat.
- Shoulder: seam to seam across the back, from shoulder point to shoulder point. This is the hardest measurement to alter.
- Sleeve: from the shoulder seam to the cuff, along the outside of the arm.
- Length: from the collar seam or waistband to the hem.
- Rise and inseam on trousers, and hip on skirts and dresses at the widest point below the waist.
Shoulder width and bust are the two numbers to take seriously, because they are the ones that cannot be changed much by a tailor. Everything else can be adjusted, at a price.
Stretch, ease and fabric behaviour
Two garments with identical measurements can fit differently because of how the cloth behaves.
Knitted fabrics stretch to the body and recover. Woven fabrics without elastane do not. A woven vintage garment has to fit as cut, which is why so many vintage pieces feel unforgiving compared with modern jersey.
Vintage garments also carry different amounts of ease — the extra room built into a pattern over the body it was cut for. A tailored jacket from an earlier era may have more structure and less ease than a modern relaxed version of the same size, or the reverse. Fitting rooms are the only way to settle this, and when there is no fitting room, measurements plus a tape measure around your own body is the best substitute.
Alterations: take in, rarely let out
Alterations expand what you can buy, but only in one direction.
Taking in is easy. Waists, side seams, hems and sleeve widths can all be reduced, within limits set by the pockets, the lining and the position of any darts.
Letting out requires seam allowance, and garments made after the middle of the twentieth century often have very little, because fabric was a significant cost and factories cut close. Older garments frequently have generous allowances and can be let out — check inside the side seams and the centre back of skirts and trousers before assuming they can.
If a garment is one size too big in the waist, it is a candidate. If it is too small across the shoulders or the bust, it is not.
Rules worth keeping
Buy for your largest relevant measurement, not your smallest. Trust the tape over the label, always. Expect an old size number to mean a smaller garment than the same number means today, and expect the difference to vary. Where a seller will not give measurements, treat that as a reason to look elsewhere rather than a reason to guess.