Men's INT to EU Clothing Size Chart

INT	UK	EU
XS	34	44
S	36	46
M	38	48
M	40	50
L	42	52
L	44	54
XL	46	56
XL	48	58
XXL	50	60
XXL	52	62

UK and US men's clothing sizes are identical, so the US column matches UK.

Letter sizes (XS to XXL) in numbers

Size	US	UK	EU
XS	34	34	44
S	36	36	46
M	38-40	38-40	48-50
L	42-44	42-44	52-54
XL	46-48	46-48	56-58
XXL	50-52	50-52	60-62

Plus and extended sizes

US	Letter	UK	EU	Chest (cm)
54-56	3XL	54-56	64-66	136-141
58-60	4XL	58-60	68-70	146-151
62-64	5XL	62-64	72-74	156-161

Note: Men's big-and-tall letter sizes are not fully standardised: some makers shift the whole ladder up, labelling a 46 to 48 inch chest as 2XL instead of XL, so these are the most common convention rather than a fixed rule. Chest in centimetres continues the site's own chart at about 5 cm per two inches.

Sources

American Roots, men's size chart (americanrootswear.com): letter to chest-inch ladder S to 5XL
sizeguide.net, men's size chart with chest in inches and centimetres to XXXL
Big Fish Clothing, Big and Tall size guide (bigfishclothing.co.uk): documents the shifted big-and-tall letter ladder
Wikipedia, US standard clothing size (references ASTM D6240 for men, chest 34 to 60)

Men's letters against the European numbers

Letter sizes are bands, not single points: on this chart a size such as INT L lines up with 2 neighbouring EU numbers, so the same letter can round either way between them. The table shows every EU value each band covers.

International letters cover pairs of European numbers, and the European figure is close to the chest in centimetres halved, so the letter rides on a metric body measurement. Asia writes the body in more openly: Chinese menswear under GB/T 1335 states height and chest in the label itself, so a letter carries far less information than the code it replaces. When Western letters meet European or Asian numbers, the chest measurement is the shared language the table falls back on.

Common questions

What does the European number under the letter measure?

Roughly the chest in centimetres halved, so a letter maps onto a metric body figure rather than a fashion label.

How do I convert a letter to a European size?

Match your chest to the numbers the letter covers in the table, since each band spans two adjacent European figures.

Men's clothing size charts · Asian clothing sizes · How to measure your body · Vanity sizing