Offset accounts are normal loan account linked to a transaction account. Interest is calculated on the net balance between the loan account and the transaction account. That is, the transaction account balance is offset against the loan balance. Fox example, if your loan balance was $100,000 and your transaction account balance is $10,000, then you would be charged loan interest on a net balance of $90,000. These products are best used for owner-occupier (or home loan) debt. The reason for this is that you are better off to offset non-deductible debt with any free cash rather than deductible debt. The only time I would recommend using an offset account is within a professional package.