What's the difference in a man's size XXL and 2XL shirt?

The wearers of each need slightly different diets.

@MeinTeil If you’re going to be the first person to respond to a question and you do so in a humorous manner, at least try to make sure your jokes are funny.

Theoretically, it’s the same size.

Of course the fit will be different depending on the manufacturer.

((Obvious troll is obvious. Again))

Checking guidelines….

My guess is, there isn’t a difference (well, there is always a difference in two random shirts from random manufacturers, be they both S, M, X, XL or XXL, i found).
But in your example, it could be that the manufacturer of the 2XL just figured that it is visibly clearer to write it in that way, as opposed to XXL.
Some people like me have difficulty reading repetitive same letters, like III or XXX.
It becomes a blur for them.
So, XXXL will be 3XL.
Or are they not so considerate?

You got that right @rebbel. I have nothing to add. :)

same thing. sometimes there isn’t a need to have the “L” there. a 3X shirt has the same meaning as 3XL. They all will shrink to some extent anyway.

XXL is the next scaled size up from XL (girth, sleeves, length, etc…). 2XL is the same dimensions as XL in all lengths and a little more girth.

They are the same.

Nothing. It’s just two different ways of writing the same thing. (In the UK it’s always XXL)