That's OK providing that you realise that 1/1/07 to 31/1/07 is one month,
but 31/1/07 to the following day, 1/2/07, is 2 months.
--
David Biddulph

"Mike" wrote in message
...
If I understand correctly then you want the difference between 2 dates
including the start and end date i.e. 1/1/2007 - 30/9/2007 would return 9.
If
my understanding is correct then this will do it.

=(YEAR(B1)-YEAR(C1))*12+MONTH(B1)-MONTH(C1)+1

Note you will have to change the cell format to General after entering
this.

Mike

"Eric" wrote:

Does anyone know how to determine the number of month between 2 periods?
such
as
23 Feb, 2006 and 1 Apr, 2006, it returns 2 months difference and not
counting the starting day. And always start to count Feb, 2006 and Apr,
2006.
Does anyone have any suggestion?
Thank you in advance
Eric