Among other things which somehow change as one crosses the Atlantic, so the standard business paper size is different in Europe. Where the standard US letter format is 216mm x 280mm or 8.50 inches x 11.00 inches the standard European A4 size for a business letter is 210mm x 297mm or 8.26 inches x 11.69 inches.
And in this particular case, size is important!
So why the difference?
This is unclear, but there is a good reason why Europe uses the size it does. A4 - the standard letter size, is a division of the A0 sheet - the starting point, if you will.
A0 is 841mm x 1189mm - which, at first glance appears arbitrary. But, if you multiply these dimensions to calculate the area of the sheet, it is (very close to) a square metre. So that makes sense.
So why not simply make a sheet that is 1,000mm x 1,000mm or a metre long on each side? The explanation for this is a little more complex.
Like many mathematical, or rather geometrical, quirks the proportion of 841:1189 is the same as 1:√2 - and if you take this proportion and divide it in two, the proportion remains the same. Thus all the paper sizes from A0 down to A8 are proportionally the same.
Looking at the sizes this becomes clearer; as A0 is divided in two A1 becomes 841mm x 594mm with what was the "short" side of the A0 paper becoming the "long" side of A1, and the short side of A1 becoming the "long" side of A2 - 594mm x 420mm and so on down to A10 which measures 26mm x 37mm or 1 x 1.5 inches.
So why is this important?
There are two principal reasons. Firstly, you will waste less paper when you print in Europe if you are printing to a standard European printing size. Because of the proportions you can fit 8 A4 pages on a standard printing sheet (which to complicate things slightly is actually 700mm x 1,000mm). Four short sides of A4 measure 210mm x 4 = 840mm and two long sides measure 594mm so there is room to mount these along with any gutters and bleed areas, crop and registration marks.
Perhaps more important, however, is the statement you are making with your printed material when you adapt to the European standard. Whilst non-standard sizes can indeed have their place, there is something familiar about standard sizing, and a European will immediately detect the size difference of any material as being "not quite right" - in the same way that a North American will notice the "strangeness" of a brochure printed in Europe.
Familiarity is often an important element which can help with trust and confidence issues. Making the effort to print materials in European sizes also shows that your company cares about the European market in and of itself, rather than as a bolt-on extension of the US.
And, whilst we are considering printing for the European market, we might also consider using UK English rather than US English, but that's a whole new can of worms, or is it beans?