I have a requirement to calculate regular monthly payments for loans which is fine with the PMT Function, however the PMT function seems to presume that the FIRST repayment is made 30 days after the loan is started. Can anyone suggest how I can adjust this calc where the first of the repayments is made immediately the loan is started and not 30 days in arrears ?

Here is a page where someone worked out the actual math behind Excel's implementation of PMT including the Type option.

It looks like the Excel formula is

PMT(interest,num_of_payments,PV,FV,Type) =

(PV* interest*(1+interest)^num_of_payments/

((1+interest)^num_of_payments-1)

+interest/((1+interest)^num_of_payments-1)*FV)*

IF(Type=0,1,1/(interest+1))

In my quick test, this matches up to what Excel gives for the same input parameters. It also matches FileMaker's PMT() for FV=0 and Type=0.

-Tom