Loan Basic app for iPhone and iPad

Installment Loan App

This app calculates any one of the four monthly installment loan factors given the other three. To use: fill in any three of the four text boxes, touch “Calculate” and the blank factor will be calculated. To clear a factor touch the circled x on the right side of the applicable text box. If all four factors are filled in the calculate will re-calculate the the previously calculated factor.

The four factors of a monthly installment loan such as a car loan or home mortgage are: 1. LoanAmt — Original loan amount,
2. IntRate — Annual interest rate being charged by the lender,
3. NuMos — Number of months required to pay off the loan,
4. MoPmt — Amount of monthly payment.

Calculation Logic:

MoPmt = LoanAmt * IntRate / (1 - (1 + IntRate) ^ -NuMos)

IntRate uses above formula to iterate IntRate from 0.0 by 0.001% until MoPmt is equal or greater than the given amount.

NuMos = Log(MoPmt / (MoPmt - LoanAmt * IntRate)) / Log(1 + IntRate)

LoanAmt = MoPmt * (1 - (1 + IntRate) ^ NuMos) / IntRate

This application rounds the results: MoPmt to nearest penny, IntRate to three decimal places, NuMos to two decimal places and LoanAmt to nearest dollar.