Some accounts allow you an interest free overdraft. This translates to letting you borrow a set amount of money for free. Not all accounts do this. The interest free amount is often less than the full overdraft limit. Be careful not to confuse the two. For example, you may have an agreed interest free overdraft of £250. But your full overdraft limit might be £1,000. You would owe interest on anything in your overdraft between £250.01 and £1,000.