American Jacket Sizes and Size Conversions

American men's jackets are sized by an even number tied to chest size, such as 38, 40 or 42, sometimes followed by S, R or L for length. UK men's numbers are the same, and EU numbers run 10 higher, so a US 40 is an EU 50. Women's U.S. jacket sizes follow dress-style numbers such as 8, 10 or 12, and letters like M or L change meaning from brand to brand.

This page is part of our jacket fit and size guide.

Key takeaways- Men: US = UK, EU = US + 10.- A "size 50" is a US 40 if it is a European label, but a US 50 is an EU 60.- The number relates to chest size but is not your chest in inches.- U.S. sizing standards are voluntary, and brands vary, sometimes by a full inch.

How American jacket sizes work

U.S. men's sizes have been based on chest measurement since at least the War of 1812, when the Army used them for ready-made uniforms. Today ASTM D6240 publishes body-measurement tables for men's sizes 34 to 60, and ASTM D5585 does the same for women's misses sizes 00 to 20.

These standards are voluntary. Most brands follow looser "catalog" sizes that have drifted over time and vary between makers. So treat any conversion as a starting point and check the brand's own chart.

The size number is a label, not a tape reading. On Leather Collection's men's chart, a US 42 fits a 40.9 in (104 cm) body chest.

Men's US jacket size conversion chart

Source: US, EU, letter and chest from Leather Collection's men's jacket chart. *UK is general guidance, not from the store: UK and U.S. men's jacket numbers match.

Other systems are general guidance only. One international conversion chart puts a US 38 at a Japanese 40. Labels from France, Germany, Italy and Spain generally use the EU column.

Jacket size 50 in U.S. sizes: if "50" is a European label, it is a US 40. If it is already a U.S. size, it is EU 60 and XXL on the chart above.

Women's US jacket sizes

Source: US, EU, letter, bust and waist from Leather Collection's women's jacket chart. *UK is general guidance, not from the store: UK women's sizes are U.S. sizes plus 4.

On this chart a women's M is a US 12 or 14. Other brands may put M on a different number, and U.S. sizes vary between makers, so compare your bust measurement rather than the letter. Some flight-jacket sellers simply tell women to buy by their dress size. Women's riding-jacket fit is covered in our women's biker jacket sizing guide.

What S, M, L and XL mean in America

There is no single U.S. letter standard. Compare two references:

The two line up roughly, but a brand can shift a letter by a whole size. For XL in leather specifically, see what size is XL in a leather jacket.

Short, regular and long

Tailored jackets, and some leather jackets, add a length letter after the number: 42S, 42R or 42L. The number stays the chest size; S, R and L are short, regular and long, chosen mainly by height. As one maker's example, Fox Creek Leather's long jackets are 2 in longer in the body and sleeve, and it suggests long for most men over 6 ft 1 in. US Wings gives the same 6 ft 1 in cut-off and says to size up when no long is offered.

Why a converted size can still fit wrong

• Brand cut. Sportsbikeshop notes Italian jackets tend to fit closer, while UK and German makers are more generous at the waist.
• Material. Decrum says leather has less give than fabric, so half a size off matters more.
• Chart type. Some charts list body measurements, others the finished jacket.

The fix is the same in every country: measure your chest, then read the brand's chart. Our guide on how to measure for a jacket size shows each tape position, and the men's leather jacket size chart covers between-sizes choices.

Order by U.S. size or by measurement

Leather Collection custom leather jackets come in standard sizes US 32-50 (EU 42-60), or you can send your own measurements instead.

FAQ

Is a 42 jacket a medium or large?

On Leather Collection's chart a men's US 42 is L. Under the European standard's chest ranges, a 40.9 in (104 cm) chest also falls in L.

Is a size 34 jacket medium or large?

Neither on this chart: a men's US 34 is S.

What is size L in America?

For men, L is a US 42 or 44 on Leather Collection's chart; for women, L is a US 16. Other brands vary.

Is a medium a US 6 or 8?

On Leather Collection's women's chart, neither: US 6 is XXS, US 8 is XS, and M is US 12 or 14. Other brands may label these sizes differently, so compare bust and waist.

What is a size 48 jacket in US sizes?

A European 48 is a US 38. A U.S. 48 is an EU 58.