Increasing your monthly payment can save you money in interest and shorten the term of your loan.
The following formula has been used:
Pleft = P*(1 -((1 + J)**t - 1)/((1 + J)**N - 1))
where, P = Principal, the initial amount of the loan
I = The annual interest rate (from 1 to 100 percent)
L = Length, the length (in years) of the loan, or at least the length over which the loan is amortized.
J = Monthly interest in decimal form = I / (12 x 100)
N = Number of months over which loan is amortized = L x 12
t=Number of paid monthly loan payments