Men's INT to US 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)

Letter sizes over the men's numbers

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

Men's S, M and L are bands, each covering more than one numbered chest size, so a letter maps to a range rather than a point. The number underneath is a chest measurement, which makes the letter a rough label on a precise base. Ease pushes it further: two garments marked L on the same chest can feel a size apart because one is cut close and the other loose. The table lists every number a letter spans so you can pin the band to your chest.

Common questions

How many US numbers does a men's letter cover?

Usually two adjacent chest sizes, so the same M or L can land on either, depending on how the garment is cut.

Should I buy by letter or by chest?

By chest. Measure around the fullest part and match the number the letter covers, since letters vary by brand and garment.

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