Offset account vs. paying down your loan

Here's the thing nobody tells you until you've already poured $40,000 into your mortgage: a dollar in an offset account and a dollar paid off your loan save you the exact same interest. Not roughly the same — identical, to the cent. The bank charges interest on your balance minus your offset, so $20,000 sitting in an offset against a 6% loan saves you the same $1,200 a year that paying $20,000 off the principal would. Same maths, same outcome on the interest line.

So if the interest saved is a tie, the whole debate comes down to one question: what else does each option do to you? And once you look at that, it stops being close.

Same interest, very different liquidity

Money you pay off your loan is gone. To get it back you have to redraw it — and a redraw is a facility your lender controls, not cash you own. Money in an offset is still your money: it's a savings account that happens to be linked to your loan. You can move it, spend it, sit on it as an emergency buffer, and the whole time it's quietly saving you the same interest as if you'd paid down the debt.

That distinction sounds academic until the day you actually need the money. Lenders can — and during stressed periods, do — freeze or reduce redraw facilities. People have found their "available redraw" cut precisely when they were counting on it. Your offset can't be clawed back like that, because the bank never had it. For an emergency fund, that's the difference between a buffer and a maybe.

The tax reason that should settle most arguments

This is the one experienced investors bring up first, and it's the strongest argument by a distance. In Australia, the tax-deductibility of loan interest is determined by what the borrowed money was used for — not by which property the loan is secured against. That rule has a brutal edge case the moment a home might later become an investment property.

Picture it. You buy a place to live in, and you diligently pay an extra $200,000 off the loan over the years. Later you decide to keep it as a rental and buy somewhere new. To fund the new home you redraw that $200,000 — and because the purpose of that redraw is personal (a home to live in), the interest on it is not deductible. You've just converted $200,000 of would-be deductible investment debt into non-deductible personal debt, and you can't undo it by shuffling money around afterwards. Over a long loan that's tens of thousands of dollars in lost deductions, gone.

Now run the same story with an offset. The $200,000 sits in the offset instead of being paid off, so the loan balance stays high and fully intact. When you move out and rent the place, the whole loan is deductible investment debt. You withdraw your $200,000 from the offset for the new home — and because that money was never part of the loan, withdrawing it changes nothing about the loan's deductibility. Same interest saved along the way; deductibility preserved. This is why so many Australian investors treat "offset, not extra repayments" as a default rule for any property that could conceivably be rented out one day.

The honest case for paying down

We're arguing for the offset, but we're not going to pretend paying down never wins. There are real, specific situations where it's the better call — and most of them are about people, not maths.

• Discipline. A large, liquid pile of cash is a temptation. If you know you'll dip into it for a holiday or a car, paying down the loan puts the money behind a friction wall — and a redraw you have to request is harder to raid than a debit card.
• The psychological win. A loan balance that visibly shrinks feels like progress in a way an offset balance doesn't. For a lot of people that emotional payoff is worth more than the flexibility they're giving up — and that's a legitimate reason, not a mistake.
• Fixed-rate loans. Most fixed loans don't offer a full offset, and many cap extra repayments. If you're fixed, paying down (within the cap) is often the only lever you have.
• Fees and rate. Offset loans sometimes carry a package fee (commonly a few hundred dollars a year) or a slightly higher rate. If your offset balance is small, the fee can eat the benefit — do the sum before you assume the offset is free.
• A guaranteed, certain result. Paying down debt is a locked-in return at your loan rate with zero risk. Some people simply value that certainty and the finality of being debt-free, full stop.

Offset vs. paying down, side by side

So who should choose what?

Strip away the theory and it comes down to your situation. Here's how we'd think about it — holding our stance, but honestly.

• Might your home become a rental one day? Lean offset, hard. The deductibility you preserve can dwarf every other factor on this page, and you can't buy it back later. If there's even a reasonable chance, keep the loan high and the cash in the offset.
• Are you an investor already? Offset, almost without exception — keep deductible debt intact and your cash liquid for the next deposit or a vacancy.
• Do you genuinely lack saving discipline? Be honest with yourself. If a liquid balance will get spent, paying down (or redraw with friction) may protect you from yourself better than an offset will.
• Are you on a fixed rate, or chasing the emotional finish line of zero debt? Paying down is reasonable — the offset may not even be on the table, and the psychological win is real.
• Is your spare cash small relative to a package fee? Run the numbers. A basic no-frills loan with extra repayments can beat a fee-laden offset you've barely funded.

The reason we keep landing on the offset is that it rarely costs you the things paying down costs you. You get the same interest saving, you keep your money, and you protect a tax position you might not even realise you'll need. Paying down asks you to give up flexibility and deductibility in exchange for discipline and a feeling. Sometimes that trade is right. Usually, in our view, it isn't.

If you want to see what either choice does to your actual loan rather than argue about it in the abstract, that's exactly what Kleev's offset and loan modelling is for. Drop in your loan, add an offset, and play with what-if scenarios — a monthly deposit into the offset, a target balance, or a growth rate — and watch the interest saved and the payoff date move in real time. Model your own loan and offset in Kleev →