Loan Payoff lets you determine how quickly you can payoff a loan by increasing your monthly payment. Just enter the current balance, annual interest rate, current monthly payment, and the additional amount to pay each month.
Loan Payoff is not designed for mortgage payoffs due to escrow payments being included in many mortgages.
A free, iAd supported version of this application is available. Just enter Loan Payoff Lite in the search window.