An offset account is a savings or transaction account linked to a loan. Any money you pay into the offset account is included when your lender calculates the interest owing on your loan. For example, if you have a $50,000 loan, and pay back $20,000, you’ll be charged interest on the $30,000 you still owe. But if you also pay $5,000 into an offset account, your lender will instead calculate your interest as if you only owed $25,000.