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R/S  \\ calculate balance, ask for amount of withdrawn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:

PMT = (-PV – FV*(SPPV(I%/12:N))) ÷ (UPSV(I%/12:N-ADV)+ADV)

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].

Ready to calculate:

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.