Article #16051: Returns the amount required to repay a debt.

 Technical Information Database

TI1051D.txt   Returns the amount required to repay a debt.
Category   :General Programming
Platform    :All
Product    :Delphi  All

Description:
PAYMENT()

Returns the periodic amount required to repay a debt.

function payment(princ, int, term: double): double;
var temp: double;
begin
  int := int / 100;
  temp := exp(ln(int + 1) * term);
  result := princ * ((int * temp) / (temp - 1));
end;

Syntax

PAYMENT(, , )



The original amount to be repaid over time.



The interest rate per period expressed as a positive decimal 
number. Specify the interest rate in the same time increment 
as  the term.  It is to be expressed as a percentage.  The 
number is divided by 100 inside the function.  



The number of payments. Specify the term in the same time 
increment as the interest.

Description

Use PAYMENT( ) to calculate the periodic amount (payment) 
required to repay a loan or investment of  
amount in   payments. PAYMENT( ) returns a numeric 
value based on a fixed interest rate compounding over a fixed 
length of  time. If  is positive, PAYMENT( ) 
returns a positive number. If  is negative, 
PAYMENT( ) returns a  negative number. Express the interest 
rate as a decimal. For example, if the annual interest rate is 
9.5%,  is 9.5 for  payments made annually.

Express  and  in the same time 
increment. For example, if the payments are monthly, express 
the  interest rate per month, and the number of payments in 
months. You would express an annual interest rate of 9.5%, for 
example,  as 9.5/12, which is the 9.5% divided by 12 months. 
The formula used to calculate PAYMENT( ) is as follows:

                           term
              int*(1 + int)^
pmt = princ * -------------------
                       term
              (1 + int)^     -  1

where int = rate / 100 (as a percentage).

For the monthly payment required to repay a principal amount of 
$16860.68 in five years, at 9% interest, the formula expressed 
as  a dBASE expression looks like this:

MyVar := PAYMENT(16860.68, 9/12, 60)       {Returns 350.00}



Reference:


7/16/98 4:34:00 PM
 

Last Modified: 01-SEP-99