Vintage sizing vs modern sizing

A short history of US women's sizes

Before mass-produced clothing, garments were made to measure. Ready-to-wear needed a common system, and the US government tried to supply one. According to Wikipedia's summary of the history:

• 1939–1940: Ruth O'Brien and William Shelton, under a Works Progress Administration grant, measured almost 15,000 women. Their proposed three-part system (combining an upper-body number, height and girth) was too complicated to manufacture and was rejected.
• 1958: the National Bureau of Standards published a bust-based system (Commercial Standard CS 215-58) with sizes 8 to 38, plus height and hip indicators.
• 1970–1971: the standard became voluntary, and a revision, PS 42-70, defined women's sizes.
• 1983: the government standard was withdrawn.
• 1995 onward: ASTM International published a voluntary standard, ASTM D5585, revised in later years including 2011.

Since the withdrawal, brands have set their own sizes. The comparison below shows the result: the same size number now describes a noticeably larger body.

Size 6–14 in 1971 vs 2011

Measurements in inches for misses' sizes. PS 42-70 figures are for women 5'2½"–5'6½"; ASTM D5585-11 figures are for a 5'5½" “straight” figure.

Misses, juniors and women's

Vintage tags also use size categories that changed less than the numbers. Misses' sizes, usually even numbers, are designed for women of about average height. Juniors' sizes, usually odd numbers (1 to 15), were cut for shorter women with a higher bust and straighter figure. Women's (plus) sizes, usually even numbers from 18 up, are for larger women of average height. Petite, tall, half-size and young-junior lines existed too, and Wikipedia notes that measurements varied by manufacturer by as much as an inch.

Shoes and other numbers

Shoe widths changed notation as well. The Vintage Fashion Guild notes that pre-1970s shoes are marked with letters from AAAA to DDD, while 1970s shoes use N, M or W — so a pair of 1940s platforms might read “7AA” where a 1970s pair reads “7N”. European and Asian shoes use the Paris Point system (38, 42 and so on).

How to measure a vintage garment

1. Lay the garment flat on a clean table without stretching it.
2. Measure across the bust (underarm to underarm), waist and hips, then double each figure.
3. Measure shoulder width, sleeve length and total length from the shoulder seam.
4. Compare with a garment you already own that fits well, measured the same way — not with your body measurements alone, since garments need ease.
5. For lingerie and bias-cut pieces, remember the fabric has more give on the diagonal; slips and gowns can measure smaller than they wear.

Measuring also reduces trying-on. Conservation guidance from the Canadian Conservation Institute advises against wearing historic costume at all, and the Smithsonian recommends keeping folding, abrasion and pressure on fragile garments to a minimum; see caring for vintage fabrics. For dating clues beyond size, see how to date vintage clothing.