Reading International Sizes Without Guessing review
US, UK, EU, IT and JP sizing are different systems, not translations of one another — and brands convert between them loosely at best. The fix is knowing which system a garment was actually cut for, and trusting centimetres over letters everywhere you can.
What we like
- Understanding the systems ends a whole category of returns
- Japanese centimetre-based sizing is the model of clarity
- Once learned, applies to every cross-border purchase forever
Flaws but not dealbreakers
- Conversion charts on retail sites are frequently approximations
- Vanity sizing corrupts letter and number sizes from within
- Shoes are worse than clothing — half sizes and widths convert badly
An Italian follows one numbering ladder, a French label a different one, a UK dress size is not a US dress size despite sharing digits, and a Japanese garment is likely sized in honest centimetres while an American one is sized in optimism. International sizing is not one system with translations — it is several unrelated systems, and the conversion chart a retailer shows you is often a loose courtesy rather than an engineering document.
The practical failures follow a pattern. Shoes are the worst offender: US, UK and EU shoe scales have different starting points and step sizes, so conversions land between sizes and every brand rounds differently — which is why the same foot owns three different numbers. Clothing adds vanity sizing on top: brands drift their labelled sizes generously over time because flattered customers buy more, so a number that fit you in one label's cut means little in another's, and even less across a border.
Worth reading alongside our Capsule Wardrobes: The Useful Idea Inside the Content Genre before you commit.
The defence is the one this whole discipline keeps arriving at: centimetres beat labels. When a listing gives garment measurements or foot-length sizing, use those and ignore the letter entirely — measure a garment that fits you, or your foot on a sheet of paper, and compare numbers. When it gives only converted sizes, find out where the brand is actually from and which system it cuts to, then convert from that origin system yourself rather than trusting the chart's arithmetic. Origin system plus real measurements resolves almost every case.
Keep the results. A note on your phone with your measurements and your landed size per brand and per system turns every future cross-border order from a coin flip into a lookup — which, given what international returns cost in postage and patience, may be the highest-value note you keep.
Key specs
- Topic
- International size systems and conversion
- Rule
- Find the system the garment was cut in; prefer measurements
