In row A I have dates 31-Jan-08, 28-Feb-08, 31-Mar-08...etc.

In row B I want an =IF function such that a certain formula will apply if
the date is 31st December, regardless of the year.

Can anyone tell me how to refer to the date in such a funtion? i.e.
=IF(A1=?????,25*3,25*4) if A1 is 31-Dec-** then 25 times 3, otherwise 25
times 4.

Many thanks for any help

Andrew