(20S, 21S): Qualifying Loan Amount (28:36 ratio)

[Eddie W. Shore]

The program presented in today's blog entry will calculate the qualifying loan amount given the following:

* Loan's annual interest rate and term (in years)
* The borrower's monthly gross income
* The borrower's monthly non-property related debt (credit cards, auto loans, store bought appliances on credit, etc). Do not include utilities or phone bills.
* The estimated monthly property tax and insurance. For this program, combine the two amounts.

Before running the program, store the following amounts in the following registers:

R0: Monthly Income
R1: Monthly Debt
R2: Monthly Property Taxes and Insurance
R3: Annual Interest Rate
R4: Term

The down payment is not taken into consideration.

The result is the loan amount using the standard 28:36 ratio (stored in register R5). The 28:36 ratio is the guideline that the borrower spends no more than 28% of their income on housing expenses, and no more than 36% of their income on all debt service.

Program:

Code:


STEP  KEY      KEY CODE
01    LBL E    61, 41, E
02    FIX 2    51, 33, 2
03    RCL 0    22, 0
04    ×        55
05    3        3
06    6        6
07    %        HP 20S: 51,14  HP 21S: 51, 53
08    =        74
09    -        65
10    RCL 1    22, 1
11    =        74
12    STO 6    21, 6
13    RCL 0    22, 0
14    ×        55
15    2        2
16    8        8
17    %        HP 20S: 51,14  HP 21S: 51, 53
18    =        74
19    STO 7    21, 7
20    RCL 6    22, 6
21    INPUT    31
22    RCL 7    22, 7
23    X≤Y?     61, 42
24    SWAP     51, 31
25    STO 8    21, 8
26    RCL 2    22, 2
27    STO - 8  21, 65, 8
28    1        1
29    -        65
30    (        33
31    1        1
32    +        75
33    RCL 3    22, 3
34    ÷        45
35    1        1
36    2        2
37    0        0
38    0        0
39    )        34
40    Y^X      14
41    (        33
42    1        1
43    2        2
44    +/-      32
45    ×        55
46    RCL 4    22, 4
47    )        34
48    =        74
49    ÷        45
50    (        33
51    RCL 3    22, 3
52    ÷        45
53    1        1
54    2        2
55    0        0
56    0        0
57    )        34
58    =        74
59    ×        55
60    RCL 8    22, 8
61    =        74
62    STO 5    21, 5
63    RTN      61, 26

Blog Entry: http://edspi31415.blogspot.com/2018/09/h...-loan.html