Shopping Smart
Why clothes fit differently in every shop, and what to do about it
A medium is not a measurement. Sizing is set by each brand against its own fit model and has drifted steadily upward for decades, which is why your size is different in every shop you enter.
There is no international standard for clothing size that manufacturers are obliged to follow. National standards exist — and are voluntary, outdated, and widely ignored.
Each brand develops its sizing against a fit model: a real person whose body defines the brand's base size. Everything else is graded up and down from that person's measurements, using rules the brand chooses.
Which means a brand's medium is a statement about one individual and a set of grading assumptions, not a measurement.
Vanity sizing
Sizes have drifted larger over decades. Analyses comparing catalogue measurements across time consistently find that a garment labelled with a given size today has considerably larger measurements than the same nominal size in the 1950s or even the 1990s.
The commercial logic is straightforward — customers respond positively to a smaller number on the label — and the effect has compounded, with different brands drifting at different rates.
The consequence for consumers is that size labels have become close to meaningless as a comparison tool, and that older secondhand garments run substantially smaller than their labels suggest.
Take your best-fitting garment in each category and measure it flat, not your body. Record:
Tops — pit to pit, shoulder to shoulder, sleeve from shoulder seam, total length.
Trousers — waist flat, rise, inseam, thigh, leg opening.
Jackets — as tops, plus jacket length from collar.
Keep the numbers on your phone. Compare against any size chart. This eliminates most sizing failure, online and in person.
Why body measurements are less useful than garment measurements
Because the relationship between a body measurement and a garment measurement is ease — the deliberate extra room designed in — and ease varies enormously by garment type, by brand and by intended fit.
A slim-fit shirt might have 10 cm of ease at the chest; a relaxed one might have 25 cm. Both are correct for what they are. Knowing your chest is 100 cm does not tell you which size to order; knowing that your favourite shirt measures 55 cm pit to pit does.
What else varies between brands
The fit model's proportions. A brand whose model has a long torso will produce garments that are long in the body for everyone.
Grading rules. How measurements increase between sizes. Some brands grade proportionally in all directions; some add width without length, which is why larger sizes at some brands are wide and short.
Target market. Brands aimed at younger customers frequently cut slimmer and shorter. Brands with an older customer base cut fuller.
National norms. Italian and Japanese sizing generally runs smaller than American or Northern European for the same nominal size. UK and US women's sizes differ by roughly four numbers.
Deliberate positioning. Some brands cut generously so customers feel good; others cut small as an implicit statement about their intended customer.
Practical strategies
Find brands that fit you and stay with them. Unglamorous and by far the most effective. Once you know a brand's medium fits your shoulders, the whole problem is solved for that brand.
Order two sizes when buying online where returns are free, and return one. Retailers dislike this and have largely priced it in.
Read reviews for fit comments specifically. "Runs small" and "runs large" from multiple reviewers is more reliable than any size chart.
Check the model information. Many retailers state the model's height and the size worn, which is genuinely useful for judging proportion.
Buy for the largest dimension and alter the rest. Shoulders and chest for tops, waist and rise for trousers, and take everything else in.
The one number that does mean something
Shoe sizing has its own chaos — UK, US, EU and Japanese systems, plus width fittings that most retailers ignore — but there is a reliable underlying measure.
Insole length, measured inside the shoe from heel to toe, is comparable across brands. Measuring the insole of a shoe that fits you well gives you a number you can ask any seller for.
And measure your feet properly, in the afternoon when they are largest, both feet, standing. Most people have one foot noticeably larger and should fit to it. Foot length changes through adulthood — feet lengthen and widen with age — so a size you have used since your twenties may no longer be right.
