The same M differs by country and by brand. How to fail less often.
Sizing is set by each brand, so two garments marked M can measure very differently, and national systems differ on top of that. Choosing by the label alone therefore fails; the measurement table on the product page is the only reliable guide. If there is none, ask, or do not buy.
You do not need every dimension. For tops, shoulder width and chest usually decide whether it works; for bottoms, waist and rise matter most. Since length is easy to alter and shoulders and waist are not, the priority is clear.
Rather than measuring your body, measuring a garment that currently fits you well, laid flat, and using those numbers fails less. Different pieces build in different amounts of ease, so body measurements alone do not tell you how a finished garment will sit. Noting your reference numbers per category keeps paying off.
At identical measurements, stretchy fabric feels roomier and stiff fabric fits exactly as measured. For knits that give, sizing slightly down often works; for denim and other stable fabrics, read the measurements literally. How much a fabric shrinks after washing also varies.
The same number belongs to different systems by country, so it cannot be transferred directly. Footwear varies most, and brands differ even within one country's system. Returns are often expensive, so checking measurements and reading what size people of similar build chose in reviews is the safer route.
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