(10C) Mortgage Loan Interest Rate

[Gamo]

This program was adapted from HP-11C Solutions Handbook on page 152

This program will calculate the "interest rate" on a loan with equal periodic payments.
The user must specify the number of periods, the present value and the payment amount.

Procedure:

n [ENTER] PV [ENTER] PMT [CHS] [R/S]

Example:

You recently obtained a $2500 car loan for 36 months.
If your monthly payment is $86.67, What is the annual percentage rate?

FIX 2
36 [ENTER]
2500 [ENTER]
86.67 [CHS] [R/S] --> 1.25 %Monthly Rate
12 [x] ---> 15.01 %Annual Rate

Program:

Code:


01  ÷
02 STO 3
03 Rv
04 STO 1
05 RCL 3
06 X^2
07 √x
08 ENTER
09 1/x
10 X<>Y
11 RCL 1
12 X^2
13  ÷
14  -
15 STO 2
16 RCL 3
17 X^2
18 √x
19 RCL 2
20  x
21  1
22 RCL 2
23  1
24  +
25 RCL 1
26 CHS
27 Y^X
28 STO 0
29  -
30  -
31 RCL 1
32 RCL 2
33 1/x
34  1
35  +
36  ÷
37  1
38  +
39 RCL 0
40  x
41  1
42  -
43 RCL 2
44  ÷
45  ÷
46 STO+2
47 X^2
48 √x
49 EEX
50  6
51 CHS
52 X≤Y
53 GTO 16
54 RCL 2
55 EEX
56  2
57  x

Gamo