How this calculator works
This converter covers three common clothing categories with genuinely different sizing logic: women's tops and dresses (sized by a numeric or letter scale), men's dress shirts (sized by neck/collar measurement), and men's trousers (sized directly by waist measurement). Pick a garment type and a size system, and it shows the equivalent sizes in every other system for that garment.
For women's tops and dresses, it also shows the body measurements (bust, waist, and hip) that a published reference chart associates with each size, in both inches and centimeters, where that chart actually documents them. Sizing conventions vary meaningfully between brands and countries, so treat every conversion here as a starting point rather than a guarantee of fit.
How the systems relate
Women's sizes: UK size = US size + 4; EU size (France/Italy/Spain-style numbering) = US size + 32.Men's dress shirts: US/UK collar size (inches) and EU/Japan collar size (cm) come from a published lookup table — collar sizing has its own historical rounding, not a plain unit conversion.Men's trousers: EU waist (cm) = US/UK waist (inches) × 2.54 — a direct, exact unit conversion, since American and British trouser sizing already uses the same inch measurement.Letter sizes (XXS-XXL) each commonly span two consecutive US numeric sizes (for example, S covers both US 6 and US 8), except XXS which covers only US 0; this calculator uses the lower of the two as the representative size for conversions.
Worked example: a women's US size 6
- US size 6 converts to UK size 10 (US + 4) and EU size 38 (US + 32).
- The same size falls in the international 'S' letter bucket, which spans US sizes 6 and 8.
- The published measurement chart for US 6 lists a 34-inch bust, 26.5-inch waist, and 37-inch hip.
- Converting to metric: 34 × 2.54 = 86.4cm bust (rounds to 86cm), 26.5 × 2.54 = 67.3cm waist (rounds to 67cm), 37 × 2.54 = 94cm hip.
Frequently asked questions
Why doesn't a converted size guarantee a good fit?
Clothing sizing is not standardized between brands or even between garment styles from the same brand — a size 8 dress from one label can fit like a size 4 or a size 12 from another (sometimes called vanity sizing). Converted sizes are a reasonable starting point, but checking the brand's own size chart against your actual measurements is always more reliable.
Why are men's shirts sized so differently from women's tops?
Dress shirts are traditionally sized by neck (collar) circumference, since collar fit is what a fitted dress shirt is built around, with sleeve length as a second measurement. Casual shirts and most women's tops instead use a size number or letter that maps loosely to a range of chest/bust measurements — a genuinely different sizing philosophy, not just a different scale.
Why do European trouser sizes look like plain waist measurements?
In much of continental Europe, trousers are commonly labeled directly by waist circumference in centimeters (so a '86' size trouser has an 86cm waist), rather than using a separate size-number scale the way jackets and suits often do. That makes the US/UK-to-EU trouser conversion a straightforward inch-to-centimeter conversion.
Why don't all sizes in the women's chart show body measurements?
This calculator only shows body measurements where the published reference table actually documents them — for sizes it doesn't cover, it tells you plainly rather than guessing at numbers. Measuring yourself directly and comparing to the nearest documented size is the more reliable approach for those sizes.
What's the most reliable way to pick a clothing size?
Measure your own bust (or chest), waist, and hip (or neck, for dress shirts) and compare directly against the specific brand's own size chart, since brands vary meaningfully even within one country's sizing system. Use this converter to translate between regions as a starting point, not a final answer.