When an Offset Account Fee Outweighs the Interest Saved

An offset account reduces the balance your lender charges interest on, usually calculated daily, so $30,000 in offset saves interest at the loan rate on $30,000. That saving is not taxed because it is a cost avoided, not income earned. On the other side sit two costs: the annual package fee, and the gap between the offset loan's rate and the cheapest basic loan you could have taken instead. In words, the comparison is interest saved on the offset balance, minus the fee, minus the rate premium on the whole loan, minus the after-tax interest the same cash would have earned in a savings account. Positive means the offset is paying for itself; negative means the fee is outweighing the saving.

The asymmetry is the whole story. The premium is charged on every dollar you owe, so 0.15% on $500,000 is $750 whether your offset holds $5,000 or $50,000, while the saving is earned only on the dollars actually in offset. A small balance faces the full premium and the full fee with very little to set against them.

At the calculator's defaults the fixed costs are $1,145 a year. The offset balance has to save more than that after allowing for the savings alternative, which is why the break-even sits near $37,700 rather than at zero. Below that balance the offset loses money every year. A $10,000 balance, for instance, saves about $610 in interest and gives up about $306 of after-tax savings interest, leaving roughly $300 of benefit against $1,145 of cost.

The answer changes when the balance grows, because the costs stay roughly flat while the saving climbs with every dollar added. Adding $300 a month lifts the balance from $30,000 to about $37,700 in a little over two years, so the account starts paying its way during year three. A bonus or tax refund brings break-even forward; a balance drawn down for a renovation or a car pushes it back out. The premium also shrinks slowly as the loan is paid down, so the calculator models each year rather than fixing the cost at $750.

Basic loans often have no annual fee but allow extra repayments and redraw. Paying the $30,000 into the loan itself saves interest at the loan rate just as an offset does, with no premium to pay. The trade-offs are practical rather than mathematical. Redraw is a request to the lender rather than an everyday transaction account, so access can be slower, may carry a minimum amount or a per-redraw fee, and the contract may let the lender restrict it, so check the terms. An offset balance is your money in a deposit account, while money paid into the loan has reduced the loan and stays there until you redraw it.

For investors the difference matters more, because the tax treatment of interest after a redraw can differ from interest on a loan with an offset attached. If the property is, or may later become, an investment, get advice from a registered tax agent before choosing between the two.

Comparing the offset loan's rate against the same lender's advertised basic rate rather than against the cheapest loan you would actually take. Counting the fee but forgetting the premium, which at the defaults is the larger of the two costs. Treating the interest saved as the whole benefit and ignoring what the cash would earn in a savings account, which turns a $685 win into a $233 loss in the example. Comparing pre-tax savings interest with the untaxed offset saving. Assuming the offset will always hold today's balance rather than modelling how it will grow or shrink. And paying for a package for the offset alone when the bundled extras, such as a credit card or fee waivers, are things you would not otherwise use.

The break-even depends on numbers the lender controls: the fee, the rate gap, whether the fee buys anything else, and what the fee-free alternative looks like. Ask these before signing and put the answers into the calculator.