HP 48G: Business Applications
Calculators Featured: HP 48G, HP 48G+, HP 48GX
Percent Addition
HP 48G Program: %PLUS
<< OVER SWAP % + >>
Stack:
2: amount
1: percent
Example 1: 150 + 17%
150 [ ENTER ] 17 (%PLUS)
Result: 175.5
To subtract, make the percent negative.
Example 2: 170 - 18%
180 [ ENTER ] 18 [ +/- ] (%PLUS)
Result: 139.4
Interest Rate Conversion to APR
The program →APR converts a nominal interest rate (NOM) to the effective interest rate (APR/EFF) given the rate and the compound periods per year.
HP 48G Program: →APR
<< "→APR"
{ { "I%YR:" } { "PYR:" } }
{ } { } { }
IF INFORM
THEN OBJ→ DROP
SWAP 1 % OVER / 1 +
SWAP ^ 1 - 100 *
"APR" →TAG END >>
Example
nominal rate: 7.5%, periods per year: 6
Result:
APR: 7.738318055 (%)
Source:
Thomsett, Michael C. The Real Estate Investor's Pocket Calculator 2nd Ed. American Management Association: New York. 2017
Present Value of a Growing Payment
The program PVGROW calculates the present value of a growing annuity. Each payment grows by the rate g% while the discount rate is r%.
PV_grow = PMT_base / (R% - G%) * (1 - (1 +G%) / (1 + R%) ^ n )
HP 48G Program: PVGROW
<< "PV GROWING ANNUITY"
{ { "1st Pmt:" } { "I/YR:" } { "Growth Rate:" } { "N: "} }
{ } { } { }
IF INFORM
THEN OBJ→ DROP 4
ROLLD 1 % SWAP 1 %
SWAP - LASTARG 1 +
SWAP 1 + / 4 ROLL 6
1 SWAP - 3 ROLLD /
* "PV" →TAG END >>
Example
1ST PMT: 1000.00
I/YR: 3.5 (%)
GROWTH RATE: 4 (%)
N: 36
Result:
PV: 37890.784118
Source:
"Present Value of a Growing Annuity" financeformulas.net https://financeformulas.net/Present_Value_of_Growing_Annuity.html Retrieved December 13, 2020.
Interest Only Loan
The program INTONLY calculates payments from:
Interest-only payment
Payment (P&I) when the principal starts being due
HP 48G Program: INTONLY
<< "INTEREST ONLY"
{ { "LOAN:" } { "I/YR:" } { "INT YRS:" } { "MAIN YRS:" } }
{ } { } { }
IF INFORM
THEN OBJ→ DROP 12
* 'N' STO ROT DUP
'PV' STO ROT DUP
'I%YR' STO 1 % * 12
/ NEG 'IMPT' DUP2
STO →TAG SWAP DROP
0 'FV' STO 12 'PYR'
STO 'PMT' TVMROOT
'PMT' →TAG END >>
Example
LOAN: 185000.00
I/YR: 4.55 (%)
INT YRS: 5
MAIN YRS: 30
Results:
IMPT: -701.4583333333 ($701.46 each month for the first 5 years)
PMT: -942.871969103 ($942.87 each month for the rest of the 30 years)
Source:
Kapfidze, Tendayi "What Is an Interest-Only Mortgage and How Does It Work?" Edited by Deborah Kearns LendingTree. LendingTree, LLC, Charlotte, NC: 2021. https://www.lendingtree.com/home/mortgage/interest-only-mortgages/ Retrieved March 9, 2021
Eddie
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