try

(Principle * i * (1+i)^n) ) / ((1+i)^n -1)
i = period interest rate (annual rate/12)
n = number of periods
====

or From Norman Harker

PMT = =-(PV*(1+RATE)^NPER+FV)/((1+RATE*TYPE)*(((1+RATE)^NPER-1)/RATE))

--
Don Guillett
SalesAid Software

"amalecki" wrote in message
...
I am using Excel 2002 I am trying to calculate a fixed monthly payment on
a
24 month loan. The problem is the bank uses a 360 day basis when they
calculate the fixed monthly payment. Excel's PMT formula has a 365 day
basis.
I have been on the Internet to no avail. I would greatly appreciate
anyone's help in solving this problem.