(12C) Simple Interest

[Eddie W. Shore]

Simple Interest Formula

T = B + B × R% × N = P × (1 + R% × N)

T = total future value (uses the FV register)
B = beginning value (uses the PV register)
R = annual interest rate (uses the i register)
N = time in years (uses the n register)

The program uses four of the TVM registers for the purpose of storing registers in a convenient way.


HP 12C Code: Simple Interest

Step : Key Code : Key

# Solve for the future value, GTO 01, R/S

Code:

01:  __, 45, 13:  RCL PV
02:  __, 45, 12:  RCL i
03:  __, 45, 11:  RCL n
04:  __, __, 20:  ×
05:  __, __, 25:  %
06:  __, __, 40:  +
07:  __, 44, 15:  STO FV
08:  43, 33, 00:  GTO 00

# Solve for the present value, GTO 09, R/S

Code:

09:  __, 45, 15:  RCL FV
10:  __, __, _1:  1
11:  __, 45, 12:  RCL i
12:  __, 45, 11:  RCL n
13:  __, __, 20:  ×
14:  __, __, 25:  %
15:  __, __, 40:  +
16:  __, __, 10:  ÷
17:  __, 44, 13:  STO PV
18:  43, 33, 00:  GTO 00

# Solve for the time in years, GTO 19, R/S

Code:

19:  __, 45, 15:  RCL FV
20:  __, 45, 13:  RCL PV
21:  __, __, 10:  ÷
22:  __, __, _1:  1
23:  __, __, 30:  -
24:  __, 45, 12:  RCL i
25:  __, __, 10:  ÷
26:  __, __, _1:  1
27:  __, __, 26:  EEX
28:  __, __, _2:  2
29:  __, __, 20:  ×
30:  __, 44, 11:  STO n
31:  43, 33, 00:  GTO 00

# Solve for the interest rate, GTO 32, R/S

Code:

32:  __, 45, 15:  RCL FV
33:  __, 45, 13:  RCL PV
34:  __, __, 10:  ÷
35:  __, __, _1:  1
36:  __, __, 30:  -
37:  __, 45, 11:  RCL n
38:  __, __, 10:  ÷
39:  __, __, _1:  1
40:  __, __, 26:  EEX
41:  __, __, _2:  2
42:  __, __, 20:  ×
43:  __, 44, 12:  STO i
44:  43, 33, 00:  GTO 00

Summary

T = B + B × R% × N

To solve for T: GTO 01, [ R/S ]
To solve for B: GTO 09, [ R/S ]
To solve for N: GTO 19, [ R/S ]
To solve for R: GTO 32, [ R/S ]


Examples

1. What is the interest rate required if you begin with $1,000.00 and end up with $1,135.00 in 5 years? Assume that account accrues using simple interest.

1000 [ PV ]
1135 [ FV ]
5 [ n ]
GTO 32, [ R/S ]

Answer: 2.70%.

2. An auto loan of $8,000.00 is to paid back in 60 monthly payments (5 years). The loan's rate is 6% at simple interest. What is the monthly payment of this loan?

The first step is to find the total amount:

8000 [ PV ]
6 [ i ]
5 [ n ]
GTO 01, [ R/S ]

T = $10,400.00 (total plus interest)

[ RCL ] [ FV ] 60 [ ÷ ]

Monthly payment with simple interest: $ 173.33


Source

Hayes, Adam. "Simple Interest: Who Benefits, With Formula and Example" Investopedia. Last updated May 27, 2023. Retrieved November 19, 2023.
URL: https://www.investopedia.com/terms/s/sim...terest.asp