On Mon, 3 Jun 2013 14:05:23 -0700 (PDT), Jan Kronsell wrote:

I have the following function =Date(1900,1,1+A1) (A1 containing 367) and it returns 02-01-1901 (Danish notation) as expected. If A1 instead contains 41012, I expect it to return 14-04-12 (41013), but it does not. It returns 16-09-89
(32767).

Is there a limitation to the final argument in the Date function, that I'm not aware of and in that case, what is it=

Jan

I cannot find any direct limitation information, but HELP does indicate that the digit is an integer. Perhaps that is why.

To accomplish the same result as what you are showing, you could use one of these formulas:

If the starting date will always be 1 Jan 1900
=A1+1

If the starting date could be some other date, a variation on:
=DATE(1900,1,1) + A1