Your answer is in the link:
Are there any prepayment penalties?
If you pay off early, you will not have to pay a penalty. You are not entitled to a refund on the origination fee and any interest that has been paid prior to the time you prepay. By prepaying, you will pay less overall interest because the loan is outstanding for a shorter time.
Interest is "earned" on the outstanding balance, if there is NO outstanding balance there is no interest earned. In other words, once you pay off the loan interest ends being charged or due.
Simple example: Say you took a $4000 30-month 10% apr loan with payments of $151.25 a month principle & Interest. Total full term payments would be $4537.37. You make 12 payments and then a lump sum for the loan (principle) balance. The first payment would break down at $117.91 to Principle and $33.33 to Interest so your loan balance would be reduced by $117.91 not the $151.25. As the loan progresses with each payment, more goes to the principle and less to the interest from each set payment of $151.25. When you lump-sum pay off the remaining principle, that's it there is no unearned (daily) interest balance.
There are amortization schedules available online that allow you to plug in numbers (starting principle, interest rates, interest per payment, etc).
