Question

181

PMT function in Javascript

rated 0 times [ 183] [ 2] / answers: 1 / hits: 36124 / 14 Years ago, mon, march 14, 2011, 12:00:00

I want to use Excel PMT function in Javascript.
The parameter would be

Pmt( interest_rate, number_payments, PV, FV, Type )

interest_rate : the interest rate for the loan.

number_payments : the number of payments for the loan.

PV : the present value or principal of the loan.

FV : It is the future value or the loan amount outstanding after all payments have been made. 



Type is : It indicates when the payments are due. Type can be one of the following values:

 0, 1

You can refer :
http://www.techonthenet.com/excel/formulas/pmt.php

this is the code I use, I am stuck in last parameter. Which is type is 0 or 1. How it effect the calculations please.

function PMT (ir, np, pv, fv ) {

 /*

 ir - interest rate per month

 np - number of periods (months)

 pv - present value

 fv - future value (residual value)

 */

 pmt = ( ir * ( pv * Math.pow ( (ir+1), np ) + fv ) ) / ( ( ir + 1 ) * ( Math.pow ( (ir+1), np) -1 ) );

 return pmt;

}

I need it in plain Javascript and not in jQuery please.

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shelbiec

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3 Years ago

answered 14 Years ago devonw · Accepted Answer

The easiest way to understand the impact of the Type parameter is to try the following values: Annual Interest = 12%, # of Months = 1, Present Value = 100

When Type=0 (the default), the PMT() function will yield 101

When Type=1, the PMT() function will yield 100

With Type=0, the interest is computed for 1 month because the payment is assumed to be at the end of the month. For Type=1, the interest is computed for 0 months because the payment is at the beginning of the month.