When mortgage rates are high, putting extra money into your offset account can feel like the most sensible financial decision on earth.

It’s safe. It’s simple. You can still access the money. And every dollar sitting there reduces the interest you pay on your home loan.

Hard to argue with that.

But here’s the question that matters if you’re trying to build wealth over the long term: is your offset account the best place for all your extra money, or could some of it be working harder elsewhere?

That’s what I’m looking at in this episode of the Financial Autonomy Essentials Series. It’s one of those questions that comes up constantly, especially when interest rates are higher and investing feels harder to justify.

The answer is not as simple as offset good, investing bad. Annoying, I know. The real answer depends on what job that money needs to do, and that’s what I unpack in this episode of the Financial Autonomy podcast.

Should I invest in shares or leave my money in an offset account?

For short-term savings, an offset account can make a lot of sense. For long-term wealth building, investing may still be the better option.

That’s the simplest way to think about it.

Some money needs to be safe and easy to access. Think emergency funds, upcoming renovations, school fees, a new car, parental leave, or money you might need if work becomes uncertain.

If you do not need it for many years, then leaving all of it in offset may feel safe, but it could come with a hidden cost: missed growth.

And this is where people often get stuck. They try to force one answer across all their money, when really, different buckets of money can have different jobs.

Some money protects you.

Some money gives you flexibility.

Some money is there to grow.

Once you see it that way, the decision becomes much clearer.

How does an offset account work?

An offset account is a bank account linked to your home loan. The money in the offset reduces the balance your lender charges interest on.

So, if you have a $500,000 mortgage and $100,000 sitting in your offset account, you are only charged interest on $400,000.

You do not earn interest on the offset account itself. Instead, you save interest on your mortgage.

That distinction matters.

Because your repayments are usually calculated on the full loan balance, the interest saving means more of each repayment goes towards paying down the loan principal. Over time, that can help you pay off the mortgage faster.

The other big benefit is flexibility. Money in an offset account is usually accessible whenever you need it. That’s why offset accounts are so appealing. They give you a lower interest benefit without locking the money away forever.

Is money in an offset really earning a return?

Money in offset is not earning interest, but it is effectively giving you a return close to the mortgage interest you avoid paying.

As at July 13 2026, the lowest advertised variable rates in Australia start from 5.69% p.a., with average market rates ranging between 6.20% and 6.92% p.a., though standard indicator rates can go much higher. Your actual rate will depend on your lender, loan type, loan-to-value ratio, repayment structure, and whether the loan is owner-occupied or investment.

That makes the offset account genuinely powerful.

If your mortgage rate is around 6.9%, every extra dollar sitting in offset is helping you avoid interest at roughly that rate. And because this is a saving rather than taxable income, the benefit is effectively after tax.

That is why the offset can be so appealing when rates are high. It is simple, flexible and tax-effective.

But it still needs to be compared properly with investing. The offset may be a great home for short-term money, emergency money and money you want to keep accessible. It does not automatically mean every spare dollar should sit there forever.

Why does tax matter when comparing offset accounts and investing?

The return from an offset account is effectively after tax, because you are not earning income that needs to be declared.

That can make an offset account more attractive than it first appears.

If you invest, you may earn income, dividends, distributions, or capital gains. Those can have tax consequences. Australian shares may come with franking credits, but you still need to factor tax into the comparison.

So, when you compare investing with leaving money in offset, do not compare a pre-tax investment return with an after-tax mortgage saving. That can make investing look better than it really is.

A fairer comparison adjusts investment returns down for tax.

That does not mean investing loses. It just means the comparison needs to be honest.

Is investing still worth it when mortgage interest rates are high?

For long-term money, investing can still make sense, even when mortgage rates are high.

The reason is simple: growth assets are designed to build wealth over time. They come with volatility, but they also have the potential to deliver higher long-term returns than cash-style options.

In the podcast, I refer to long-term market return data showing average returns over the 30 years to the end of the 2022 financial year of 9.8% per year for Australian shares and 11.7% for US shares in Australian dollars.

Of course, past returns do not tell us what the future will be, but 30 years is still a useful reference point when thinking about long-term money.

The key phrase there is long term.

If you might need the money in the next year or two, investing it may expose you to risk you do not need. Markets can fall at exactly the wrong time and your offset account does not have that problem.

But if the money is genuinely for the future, investing can still deserve a serious look.

How does inflation impact money in your offset account?

Inflation matters because money that feels safe can still lose buying power over time.

Let’s say you leave $100,000 in offset for several years. The number on the screen may still say $100,000, but what that money can buy may have gone backwards.

That is the problem with cash.

It feels safe because the balance does not bounce around like an investment portfolio. But over time, inflation can still do damage.

This does not mean you should avoid offset accounts. Not at all. It means you need to be clear on why the money is there.

When should you keep money in your offset account?

Keeping money in offset can make sense when you need safety, flexibility or certainty.

This might include money for your emergency fund, upcoming expenses, home repairs, renovations, school fees, a planned car purchase, parental leave, a career break, or extra breathing room while mortgage repayments are high.

There is nothing wrong with keeping money in offset when it has a clear job.

In fact, it can be a very smart move. The danger is when all your money ends up there by default because it feels safer than making a decision.

That’s when the offset can become a hiding place, not a strategy.

When should you consider investing in shares instead?

Investing may be worth considering when the money is genuinely long term and you have enough cash available for short-term needs.

This might be money you do not expect to touch for at least five to seven years, or longer. It might be surplus savings after your emergency fund is sorted. It might be part of a broader plan to build wealth outside the family home.

The family home is important, but it is not always enough on its own.

A paid-down mortgage can reduce stress and improve cash flow, but it does not automatically create a diversified wealth strategy. If all your spare money goes into the home loan or offset, you may end up asset-rich but lacking flexibility later.

That’s why investing can still play a role, even while you have a mortgage.

The question is not should I invest or use offset?

A better question is how much should go towards security, and how much should go towards growth?

What is the biggest mistake people make when deciding between an offset account vs investing in shares?

The biggest mistake is treating this as an all-or-nothing decision.

People often think they have to choose one team. Team Offset or Team Invest.

When you can actually do both. You might keep your emergency fund and short-term savings in offset, while investing money that is intended for the long term.

That approach can give you the best of both worlds: flexibility today and growth potential for the future.

The other mistake is comparing the two without factoring in tax, inflation, risk and timeframe. Once you include those, the answer usually becomes more personal.

And that’s the point. This decision should not be based on what your friend did, what someone on Reddit says, or a hot take from a finance influencer.

It should be based on your mortgage, your income, your goals, your risk tolerance and your timeframe.

So, which one could make you richer?

Investing has the potential to make you richer over the long term, but an offset account may be the smarter place for money you need soon or money you cannot afford to put at risk.

That is the trade-off.

Offset accounts are excellent for short-term money because they are flexible, accessible and tax-effective. Investing is usually better suited to long-term money because it gives you the chance to grow your wealth over time.

The right answer is often a mix.

Keep enough in offset to feel secure and cover known short-term needs. Then look at whether surplus long-term savings could be invested in a way that fits your broader financial plan.

Done well, this is not about chasing the highest return. It is about making sure each dollar is doing the right job.

What should you do before deciding?

Before you move money into investments or leave everything sitting in offset, ask yourself:

When will I need this money?
What would happen if my income changed?
Do I already have a proper emergency fund?
Am I using the offset because it fits my plan, or because investing feels uncomfortable?
Have I compared the after-tax outcome properly?
Am I building wealth outside the family home?
Is this decision helping me move towards the life I actually want?

That last one matters more than people think. Money decisions are not just maths problems, they need to help support the life you are trying to build.

Need help deciding what is right for you?

If you have extra money available and you’re unsure whether to keep it in offset, pay down the mortgage, invest, or do a bit of each, it’s worth getting advice before making the call.

At Guidance Financial Services, we help clients understand their options and test different strategies before they make big financial decisions.

We do not have an investment product to sell. Our job is to help you work out what makes sense for your circumstances, your goals and the future you’re trying to build.

You can book an appointment below.

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This article is for educational purposes only and does not take into account your individual circumstances. If you would like tailored advice, we can help you work through the numbers properly.