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Read any size tag, in any system, before you buy.
Instant clothing and shoe size conversions between US, UK, EU and international systems — plus how to measure yourself so the size you pick is one you can trust.
Pick a garment and two systems above, or jump straight to a conversion below.
Most searched conversions
Why SizeDecoder
Sizes don't map cleanly
A US 8 isn't a fixed distance from a UK 8 or an EU 40 — the systems were built on different measuring conventions, and no single formula converts one to another with certainty. We show the standard conversion, and say plainly where it's an approximation.
Brands don't agree with each other
Two dresses labeled the same size from two different brands can differ by inches. A conversion chart gets you to the right neighborhood; the garment's own size chart gets you the rest of the way. We tell you to check both.
Measuring yourself is the fix
Every conversion page links to the matching measure-yourself guide, so you're not just trusting a size label — you're checking it against your own body.
At a glance
Why size conversion is harder than it looks
Most size conversion charts online are copied from a single retailer and presented as if they were universal fact. They aren't, because there's no international standards body that regulates clothing or shoe sizing the way there is for units of length or weight. US shoe sizing grew out of an old inch-based last measurement; UK sizing grew out of a related but separately calibrated inch-based system (the barleycorn); EU sizing grew out of the French Paris-point system, a centimetre-based unit with no shared origin with either English-speaking convention; and Japanese and Korean sizing simply state the foot length itself, in centimetres or millimetres. None of these were ever meant to line up with each other — the conversion tables you find anywhere, including on this site, are compiled approximations of where the systems land relative to one another today, not a fixed physical law.
On top of that structural mismatch, individual brands drift. American clothing sizing specifically has been affected by decades of “vanity sizing,” where the same actual body measurements get labeled with a progressively smaller number over time to flatter the buyer — meaning a size 8 today doesn’t represent what a size 8 meant twenty years ago, and it doesn’t represent the same measurements at every brand today either. A conversion chart can translate between systems; it can’t undo decades of individual brands quietly redefining their own numbers.
That's the honest starting point for everything on this site: every chart and every conversion page here is compiled from standard, widely published sizing conventions, dated and sourced on the methodology page, and presented as the best general answer available rather than a guarantee. The most reliable second check, once you have a converted size, is comparing it against the specific garment's own chart and — if the purchase genuinely matters — against your own measured figures using one of the measuring guides on this site. A conversion gets you to the right neighborhood; measuring yourself is what confirms the address.
Frequently asked questions
Why don't clothing and shoe sizes just use one universal system?
Because sizing conventions were built independently by different countries and industries over more than a century, using different base units (inches, French Paris points, direct centimetre foot length), long before any international standard existed to unify them — and no such standard exists today either.
Is a converted size guaranteed to fit?
No — it's the standard published relationship between two systems, not a guarantee for any specific brand. Brands vary in cut, and vanity sizing has shifted what a given number represents over time, so checking the specific brand's own chart matters for anything you can't try on.
Why does this site also explain how to measure yourself?
Because a size conversion is only as reliable as the number you're converting — a guessed size compounds with any conversion imprecision, while an accurately measured figure gives the conversion the best chance of landing correctly.
How current are the size tables on this site?
They're compiled from current standard sizing conventions and reviewed periodically — see the methodology page for the specific review date and sourcing approach.