How to size underwear correctly
Measure first, label second
Pick a tape measurement and match it to the chart. Labels (S/M/L, US/UK/EU numbers) drift between brands; the underlying body measurement does not. Hip circumference at the widest point and natural waist. Underwear sizes are based on hip first, waist second, in most charts.
Picking between two sizes
Pick the smaller for boxer briefs and bikinis (they're cut with stretch). Pick the larger for boxers and high-rise styles where the waistband digs in if too tight.
Brand and regional variation
The same labeled size can differ by a full size between brands and regions. Asian brands generally run a half size smaller than US brands; European brands fall in between. When in doubt, use the centimetre or inch measurement on the size chart, never the letter.
Common mistakes
- Sizing by your old favourite without checking the new brand's chart.
- Skipping the measurement step. Body shape changes; old numbers go stale.
- Picking too tight in non-stretch fabrics — they don't break in the way leather does.
- Trusting a single review's "runs small / runs large" without looking at the reviewer's measurements.