I made the mistake recently of ordering some shirts online from the Mozilla Store in the US. Of course, I (foolishly) just bought what I thought was the correct size, without realising that the sizes in the USA are different to those we use here in Australia. I take a 3XL shirt size here in Australia, which means about a 46 inch chest size. In the US, a 3XL chest size shirt is actually between 54 and 56 inches !!! As a result, the shirts I bought were like tents on me, and totally unsuitable.
I did a bit of research and found comparisons of sizes for mens shirts between the US and AUS, so I thought I’d make a table for future reference. What I found was that I should have bought a US size XL – that would be plenty big enough for me.