## Sunday, August 7, 2016

### HP 12C Programming III: Refinancing, Advance Payments in a Lease, NPV, NFV, NUS

HP 12C Programming III: Refinancing, Advance Payments in a Lease, NPV, NFV, NUS

HP 12C Programming Part I:  Modulus, GCD, PITI

HP 12C Programming Part II:  Weekday Number, Gross Up Calculation

HP 12C Refinancing:  When refinancing “resets” the clock.

Sometimes when a long term mortgage is refinanced, the original length of term is reset.  We will assume payments are made monthly.

Input:

Store the following amounts in the registers:

Clear the TVM variables by pressing [ f ] [x<>y] (CLEAR FIN)
Original number of payments,  [ n ]
Annual rate, [ 12÷ ] [ I ]
Loan Amount, [ PV ]

Number of payments that have been made prior to refinance, [STO] [ 0 ]  (R0)
New annual rate, [ENTER], 12, [ ÷ ], [STO] [ 1 ]  (R1)

Run the program by pressing [R/S].  The original payment is calculated.  Press [R/S] again to get the balance.  Enter any additional monies (can be \$0.00) received due to the refinance.  Finally, press [R/S] again, and the new payment is calculated.

Program:
 STEP CODE KEY 01 45, 11 RCL n 02 44, 2 STO 2 03 14 PMT 04 14 PMT \\ calculate payment 05 31 R/S 06 45, 0 RCL 0 07 11 n 08 15 FV 09 31 R/S  \\ calculate balance, ask for amount of withdrawn 10 30 - 11 16 CHS 12 13 PV 13 0 0 14 15 FV 15 45, 1 RCL 1 16 12 i 17 45, 2 RCL 2 18 11 n 19 14 PMT 20 43, 33, 00 GTO 00

Example:

A couple purchased a house for \$185,000.  The mortgage lasts for 30 years (360 months) with a 4.8% interest rate (0.4% periodic rate).   180 payments have passed, and the couple is able to refinance the mortgage (but pay that amount in 30 years) at a rate of 3.84%.  \$15,000 is also cashed out.

Input:

360 [ n ]
0.4 [ i ]
185000 [PV]
180 [STO] [ 0 ]
0.32 [STO] [ 1 ]

Results:

[R/S]    -970.63  (The original payment is \$970.63)
[R/S]    -124,373.78   (Balance of \$124,373.78)
Enter 15000, press [R/S] -652.60   (New payment is \$652.60)

HP 12C:  Advance Payments in a Lease

The program calculates the payment where you pay number of payments in advance.

Formula:

Where:
SPPV:  present value of \$1, where FV is equal to 1
USPV:  present value of \$1, where PMT is equal to 1

Input:

Number of payments, [ STO ] [ 0 ]
Number of payments made in advance, [ STO ] [ 1 ]
Periodic Rate, [STO] [ 2 ]
Price of the Lease, [STO] [ 3 ]
Salvage Value, [ STO ] [ 4 ]

Calculate lease payment by pressing [R/S].

 STEP CODE KEY 01 42, 34 Clear FIN  ([ f ] [x<>y]) 02 1 1 03 16 CHS 04 15 FV 05 45, 2 RCL 2 06 12 i 07 45, 0 RCL 0 08 11 n 09 13 PV 10 45, 4 RCL 4 11 20 * 12 16 CHS 13 45, 3 RCL 3 14 30 - 15 45, 11 RCL n 16 45, 1 RCL 1 17 30 - 18 11 n 19 45, 15 RCL FV 20 14 PMT 21 0 0 22 15 FV 23 13 PV 24 45, 1 RCL 1 25 40 + 26 10 ÷ 27 43, 33, 00 GTO 00

Example:

A machine with a cost of \$40,000.00 is leased for 48 months.  Two advanced payments are required.  Interest rate is 10% (monthly periodic rate is 10%/12).  The residual value is estimated to be \$15,000.

Input:

48 [STO] [ 0 ]   \\ term
2 [STO] [ 1 ]   \\ 2 advanced payments
10 [ENTER] 12 [ ÷ ] [STO] [ 2 ]  \\ interest rate
40000 [STO] [ 3 ]  \\ cost
15000 [STO] [ 4 ] \\ salvage value

Result:

[R/S]  -1249.30    (Each payment is \$1,249.30.  Two advanced payments are \$2,498.60).

Source:  HP 17bII+ Financial Calculator User’s Guide.  Hewlett Packard.  Edition 3:  2007

HP 12C: Net Present Value, Net Future Value, Net Utility Stream

Input:

Clear the registers/finance registers
Press [ g ] (GTO) 00 to get the pointer to line 00.  (000 for the HP 12C Platinum editions.  Remember, the Platinum editions have up to 400 steps and line numbers are in triple digits)
Store -1 in [ n ] (don’t worry, n is incremented in the main loop)
Store periodic interest rate in [ i ].
Store 0 in register 0  (0 [STO] [ 0 ]).  Register 0 is use for calculating NPV

Enter each cash flow one at a time, and press [R/S].

Press [ g ] (GTO) 10  (or 010) to get the pointer to line 10.
Press [R/S] to get NPV (net present value)
Press [R/S] to get NFV (net future value)
Press [R/S] to get NUS (net utility stream)

Program:
 STEP CODE KEY 01 16 CHS  // main loop: input data 02 15 FV 03 45, 11 RCL n 04 1 1 05 40 + 06 11 n 07 13 PV 08 44, 40, 0 STO+ 0 09 43, 33, 0 GTO 00  // finish main loop 10 45, 0 RCL 0 // calculation part 11 31 R/S  // net present value 12 1 1 13 16 CHS 14 13 PV 15 0 0 16 14 PMT 17 15 FV 18 45, 0 RCL 0 19 20 * 20 31 R/S  // net future value 21 45, 0 RCL 0 22 1 1 23 16 CHS 24 14 PMT 25 0 0 26 15 FV 27 13 PV 28 10 ÷ 29 31 R/S  // net utility stream

Example:

Rate:  15%
 Cash Flow # Flow 0 -10,000.00 1 2500.00 2 3500.00 3 5000.00 4 5000.00

Input:
[ f ] CLEAR FIN, [ f ] CLEAR PRGM
-1 [ n ]  // do this on each new problem
0 [STO] [ 0 ]   // do this on each new problem

15 [ i ]
10000 [CHS] [R/S]
2500 [R/S]
3500 [R/S]
5000 [R/S]
5000 [R/S]

Results:

[GTO] 10  [R/S]:   NPV = 966.76
[R/S]:   NFV = 1690.88
[R/S]:   NUS = 338.62

Input slowly and carefully.

This blog entry is property of Edward Shore, 2016.

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