Why this matters
Shopping for clothing across international retailers is a guessing game without a reliable size conversion reference. A US medium is not a UK medium, and neither maps cleanly to an EU medium. The numbers follow different measurement philosophies — US sizes are loosely based on chest circumference in inches, UK sizes follow a similar but not identical scale, and EU sizes approximate chest circumference in centimeters. The result is constant confusion, especially when ordering online from a brand based in another country.
The problem compounds when you factor in vanity sizing, where brands intentionally label larger garments with smaller numbers to appeal to customers. A size 38 from a European fashion house may fit differently than a size 38 from a European outdoor brand. No conversion tool can eliminate this brand-to-brand variance, but a well-built converter gives you a reliable starting point that is far more useful than guessing.
This converter works with four input systems — US, UK, EU, and direct chest circumference in centimeters — and outputs approximate equivalents in every system plus a letter size from XS to XXL. The letter size mapping is based on chest circumference bands, which provides a more stable reference point than the arbitrary numbers that vary by region.
Reference table
| Letter size | Chest (cm) | US | UK | EU |
|---|---|---|---|---|
| XS | ~86 | 34 | 34 | 44 |
| S | ~90–94 | 36 | 36 | 46 |
| M | ~96–102 | 38–40 | 38–40 | 48–50 |
| L | ~104–110 | 42–44 | 42–44 | 52–54 |
| XL | ~112–118 | 46 | 46 | 56 |
| XXL | 120+ | 48+ | 48+ | 58+ |
How to use it
Enter the size value you know — this could be a US number like 42, a UK number, an EU number like 52, or a chest measurement in centimeters.
Select the source system from the dropdown: US, UK, EU, or chest in cm.
View the approximate equivalents displayed in all four systems along with the corresponding letter size.
Always cross-reference with the specific brand's size chart before making a purchase.
Testing your result
Cross-check the converter output against a garment you already own that fits well. Measure your chest circumference with a tape measure, enter it in centimeters, and verify that the resulting letter size matches the label on your best-fitting shirt. If you typically wear a US 42 and the converter confirms that your 106 cm chest maps to US 42 and EU 52, the tool is working correctly for your body. Small deviations of one size are normal due to brand variance.
Common mistakes
Assuming the conversion is exact — these are approximations based on general industry standards, and individual brands vary significantly.
Using this tool for women's clothing, which uses a different size scale (women's US sizes are roughly 1.5 sizes larger than men's for the same body).
Applying adult conversions to children's sizes, which use entirely different age-based and height-based scales.
Forgetting to check the specific brand's size chart, which is the only way to get a truly accurate fit.
Edge cases and options
The chest circumference input is the most reliable entry point because it bypasses the regional numbering systems entirely and maps directly to a physical measurement. If you are between sizes, the chest measurement tells you whether to size up or down. The tool is designed for men's adult clothing only. Women's clothing and children's clothing follow fundamentally different sizing systems and require dedicated conversion tools. The EU size column roughly approximates chest circumference in centimeters, which is why EU sizes tend to be much larger numbers than US or UK sizes.
Real-world use cases
Ordering a shirt from a European brand's website when you only know your US size and want to avoid ordering the wrong fit.
Checking whether a UK size 40 jacket will fit someone who wears a US 40 — the numbers are close but not always identical.
Converting a chest measurement taken at a tailor into a letter size for quick online shopping.
Frequently asked questions
Q: How accurate are the conversions?
A: Approximate — brands use different size tables. Always check the specific brand's size chart for important purchases. Letter sizes use chest circumference bands.
Q: What's the chest measurement basis?
A: XS is around 86 cm, S is 90–94, M is 96–102, L is 104–110, XL is 112–118, and XXL is 120 and above. EU size approximately equals chest in cm.
Q: Does this work for women's clothing?
A: The tool uses men's adult formulas. Women's US sizes are roughly 1.5 sizes larger than men's for the same body. Use a dedicated women's chart.
Q: What about children's sizes?
A: Children use entirely different scales based on age and height. This tool is adults-only.
Q: Why do different brands have different sizes for the same label?
A: Vanity sizing and regional fit preferences cause brands to shift their size charts. Always consult the brand's own chart for accuracy.
Start using it now
Try the Clothing Size Converter tool. See also Shoe Size Converter, Ring Size Converter, and Height Converter.
