clearing personal loan early

Hey... long time reader, first time poster.

Quick question on calculating the early repayment of a personal loan.

If i had a loan for 20,000 (payment protection of approx 2500) and total cost of credit of approx 5000 (apr 8.5) and i wanted to pay it off 1 year early (of 5 year loan) whats the easiest way to calculate the settlement figure? also there is approx 8000 left including intrest + payment protection

Any help would be much appreciated.

The terms & conditions of the credit agreement should explain how to calculate any early redemption amount and penalties (if applicable).