To get help on EOMONTH, type EOMONTH into Excel help.

DATE(A1,B1+1,1) is the first day of the month after B1; DATE(A1,B1+1,0) is
1 day before that, and is therefore the last day of month B1.

Stefi said "month No in B1" so, no, the month number should *not* be
alphabet; it should be 10, not "ten".
--
David Biddulph

"yclhk" wrote in message
...
Thanks Ron & Stefi.

My MS office returns that the EMONTH function cannot be found. My MS
office
is Office XP. Does the function not inclduding in this version.

The Date(year, month, day) formula is found worked. Pls be kind to
explain
that :
- why the month value should add 1, i.e. B1+1
- does the value in B1 must be alphabet

Thanks a lot,


"Stefi" wrote:

Having year in A1, month No in B1:
=DAY(DATE(A1,B1+1,0))

Regards,
Stefi

"yclhk" ezt írta:

I prepare a report containing the daily average for every month in the
year.
How can I set the formula (prefer not VBA) which can automatically
identify
number of days for every month, i.e. in August, get the average of
dividing
by 31; in September, get the average by dividing of 30 and so on ?