Mortgage offset accounts have steadily increased in popularity since they were introduced in Australia in the late 1980s. The pitch is compelling: every dollar sitting in the offset reduces the loan balance your interest is calculated on, effectively earning you your mortgage rate, tax-free, while staying fully accessible.
For many borrowers that is exactly how it plays out. But "popular" and "always best" are not the same thing, and for some households an offset account quietly costs more than it saves.
How an offset actually earns its keep
Interest on a home loan is calculated daily on the net balance — the loan amount minus whatever sits in the linked offset account. With a $500,000 loan at 6% and $30,000 in the offset, you pay interest as though you owed $470,000. That saving compounds because your repayments stay the same, so more of each repayment reduces the principal.
The benefit is real, but it scales with the balance you actually keep in the account. An offset holding a few thousand dollars saves only a few hundred dollars a year — often less than the cost of having the feature.
The catch: offsets are rarely free
Offset accounts usually come attached to package loans carrying annual fees of $300–$400, or to interest rates slightly higher than a no-frills equivalent. If your average offset balance is modest, a basic loan with a redraw facility and a lower rate can leave you ahead.
As a rough rule, the fee only pays for itself once your average offset balance clears a meaningful threshold — for many products, somewhere in the $20,000–$40,000 range. Below that, you may simply be paying for a feature you can't use.
Offset vs redraw: the tax wrinkle
For owner-occupiers who will never rent out their home, offset and redraw feel interchangeable. But if there is any chance your current home becomes an investment property later, the difference matters enormously.
Money withdrawn from an offset doesn't change the loan balance, so the full loan can remain deductible once the property is rented. Money redrawn from the loan itself, however, creates a new borrowing whose deductibility depends on what you spend it on. Choosing the wrong structure now can permanently shrink your future tax deductions.
So who should — and shouldn't — have one?
Offsets tend to suit borrowers with healthy and stable cash balances, salaries paid directly into the account, or plans to convert their home to an investment property. They suit disciplined spenders, because the money remains only a tap away.
They are a poorer fit for borrowers with small savings balances, those prone to spending accessible cash, and those for whom a lower headline rate on a basic loan simply saves more. The honest answer is that it depends on your numbers — which is exactly the kind of comparison a broker or adviser can run for you in minutes.
Key takeaways
Any investment information and general advice displayed or given on this website does not take into account any person's personal objectives or financial situation. You should consider the general advice having regard to your own circumstances.
