Find your jacket and coat size from body measurements. Convert between US, EU, UK, and IT sizing systems for men's and women's jackets.
Finding the right jacket size is surprisingly complex because sizing systems vary wildly between countries, brands, and garment types. A US 40 Regular, an EU 50, a UK 40, and an IT 50 are all roughly the same size — but knowing that requires a conversion table. This jacket size calculator takes your body measurements and recommends your size across all major systems.
The calculator accounts for chest circumference (the primary sizing measurement), shoulder width, arm length (for sleeve fit), and torso length (for Regular, Short, and Long designations). Men's and women's sizing use different scales, and the tool handles both. It also factors in the difference between "body measurement" and "garment measurement" — jackets are designed with 3-5 inches of ease beyond your actual chest size.
Whether you're shopping online, buying from European brands, or finding your suit jacket size for an event, this calculator eliminates guesswork. It also provides tips for borderline sizes, layering considerations, and how different jacket styles (athletic fit, slim fit, classic fit) affect sizing. That makes it easier to choose a size that works before you rely on a tailor or make a return.
It gives you a starting size across multiple markets before you order online or compare brands. That is much more reliable than guessing from a generic S, M, or L label alone. It also helps when you are comparing suit jackets, blazers, and coats that share the same base number but fit differently.
US Men's jacket size ≈ chest measurement in inches (rounded to even number). EU size = US size + 10. UK size = US size. IT size = US size + 10. Women's US size = (chest − 28) ÷ 2 (approximate). Short/Regular/Long based on torso length.
Result: US 40R, EU 50, UK 40, IT 50
A 40-inch chest corresponds to US size 40. Regular length for average torso. EU conversion adds 10 (US 40 = EU 50). UK uses the same system as US for men's jackets.
Chest circumference is still the anchor measurement for most jacket systems, but shoulder width, sleeve length, and body height determine whether the suggested size should be Short, Regular, or Long. Taking measurements over a light shirt usually gives the best baseline because it reflects how the jacket will actually be worn.
Jackets are cut with ease so that you can move, layer clothing, and button the front without strain. Slim tailoring uses less extra room than classic cuts, so two jackets with the same tagged size can feel very different. That is why the calculator can only give a starting point, not a guaranteed fit across every brand.
US, UK, EU, and IT systems often map closely, but manufacturers still change the block, shoulder shape, and sleeve proportions. Use the result to narrow your search, then compare it against the brand's own chart before ordering. This is especially important for fashion labels and made-to-measure lines that run intentionally slim or relaxed.
Wrap a tape measure around the fullest part of your chest, under your arms and across the shoulder blades. Keep the tape snug but not tight. Breathe normally and take the measurement on an exhale.
These refer to torso/sleeve length, not body height. Short fits men under 5'7" (women under 5'3"), Regular fits 5'8"-5'11" (5'4"-5'7"), Long fits 6'0"+ (5'8"+). Actual cutoffs vary by brand.
If you plan to wear thick sweaters or multiple layers under a jacket, consider going one size up. This adds about 2 inches of chest room. For light layering (just a shirt), your regular size works.
They use the same size numbers, but sport coats/blazers often have slightly roomier cuts. If you're a borderline size, a sport coat might fit at your exact size while a suit jacket needs the next size up.
Classic fit: 4-6 inches beyond chest measurement. Slim fit: 2-3 inches. Athletic fit: 3-4 inches with a broader shoulder. You should be able to button the jacket without pulling and slide a flat hand inside.
No. EU sizes are typically US size + 10. So US 40 = EU 50. However, some European brands use their own proprietary sizing. Always check the brand's specific size chart when available.