My client has used PMT function as part of their loan
calculations. I'm having to reproduce all calculations
into a stored procedure. I've been looking around for the
exact formula calculations that PMT does with the values
and I can't seem to find the calculations any where. Can
you help?

"Sam" wrote in message
...
My client has used PMT function as part of their loan
calculations. I'm having to reproduce all calculations
into a stored procedure. I've been looking around for the
exact formula calculations that PMT does with the values
and I can't seem to find the calculations any where. Can
you help?

I doubt very much that you can get hold of Microsoft's algorithms. The
formula Excel uses is probably of the form:

Payments = Loan amount / annuity factor

Where annuity factor is given by the formula

(1 - (1+I)^-N) / I

I is the interest rate
N is the number of payments

There are variations depending on whether payment is in advance or in
arrears

The above annuity factor is for arrears - multiply the annuity factor by
(1+I) for in advance payments

Also the MS function includes a possibility of a balloon payment at the end
of the mortgage but your client may not use that. If he does, reduce the
loan amount by

Balloon payment * (1+I)^-N

That's it.

GB

Look in Excel Help at the PV function. This gives you the algorithm. You
need to do a little algebra to derive the equation used for PMT.

--
Regards,
Tom Ogilvy


"Sam" wrote in message
...
My client has used PMT function as part of their loan
calculations. I'm having to reproduce all calculations
into a stored procedure. I've been looking around for the
exact formula calculations that PMT does with the values
and I can't seem to find the calculations any where. Can
you help?