I don't know how you can differentiate between 28-31 day months, since you're
adding periods that have various beginning and ending months. Here's what
you could try using the given information, and assuming an average
30.4375-day month:

total years = SUM(C2:C4)+FLOOR(SUM(D2:D4)/12,1)
[adds a year for every 12 months in column D]

total months =
SUM(D2:D4)-FLOOR(SUM(D2:D4)/12,1)*12+FLOOR(SUM(E2:E4)/30.4375,1)
[removes months that are accounted for in column C, adds a month for every
30.4375 days in column E]

total days = SUM(E2:E4)-FLOOR(SUM(E2:E4)/30.4375,1)*30.4375
[removes days that are accounted for in column D]

"catrrmg" wrote:

Hi again! It just got slightly more complicated (or at least for me). Here is
an example to get the problem more clear: Mister X worked for a couple of
periods in our company:
start date end date years months days
19.12.2003 13.09.2005 1 8 25
09.10.2005 01.11.2006 1 0 23
09.11.2006 20.01.2008 1 2 11
total 3 10 59
As we see it the ex the # of days corresponds to more than a month. The
question is: how do I convert if it is necessary the # of days in months,
months years, taking into consideration that a month could be 28, 29, 30
and 31 days long.
Thanks very much in advance.