August 2026 CPI: Inflation Hits 4% — What It Means for the Next RBA Rate Rise and Your Mortgage

Australia's headline inflation rose to 4.0% in the year to August 2026, up from 3.5% in July, according to the ABS monthly CPI released at 11:30am on Wednesday 30 September 2026. The measure the RBA watches most closely, trimmed mean inflation, held steady at 3.6% for a third month. The figures came a day after the RBA lifted the cash rate to 4.60%.

For Melbourne mortgage holders, the key question is whether another rate rise is coming. Below, we set out what the numbers show, what economists and markets are saying, and the dates that will decide the RBA's next move.

What Was Australia's Inflation Rate in August 2026?

Annual headline inflation was 4.0% in August 2026, up from 3.5% in July. Prices rose 0.4% over the month. Trimmed mean inflation, which removes the biggest price swings, was 3.6% for the third month in a row. Both measures remain above the RBA's 2–3% target band, according to the ABS.

The ABS said housing was the largest contributor, rising 5.7% over the year, driven by new dwelling costs (up 5.4%) and electricity. Transport was the second-largest, up 5.6%. Automotive fuel jumped 14.8% in August alone, reflecting higher world oil prices and the unwinding of federal fuel excise relief. ABS head of price statistics Rachael McCririck noted that trimmed mean inflation "remained steady at 3.6 per cent" for the third straight month.

Why Does the Trimmed Mean Matter More Than the Headline?

Headline inflation includes every price change, so short-term shocks such as petrol spikes or the end of government rebates can push it up or down sharply. The trimmed mean removes the largest rises and falls each month, which gives a clearer read on underlying price pressure. That is why the RBA focuses on it when setting rates.

Read that way, August was mixed but not alarming. The jump to 4.0% came mostly from fuel and energy, while underlying inflation did not speed up. Monthly trimmed mean inflation rose 0.2%, below the 0.3% economists had expected, according to market data service investingLive. The headline figure was in line with, or slightly below, forecasts. ABC business editor Michael Janda noted that a Reuters poll had expected 4.1%.

Underlying inflation is still well above the target band, however. Energy costs flowing through to other prices, which economists call second-round effects, are a risk the RBA has flagged repeatedly. For a deeper look at the energy and spending debate behind this week's decision, see our analysis of government spending, GDP and the RBA.

Will the RBA Raise Interest Rates Again in November 2026?

It's possible but not certain. Markets cut the odds of a November rise after the CPI release. Economists are split: Westpac expects another increase, while CBA and NAB expect a hold with a risk of further rises. The September-quarter CPI in late October is likely to decide the RBA's next move.

What economists are saying

• Westpac chief economist Luci Ellis said before the release that another November rise is now Westpac's base case. She described the bar for a follow-up hike as "low" (ABC, 30 September).
• CBA and NAB are forecasting a hold in November but warn that more rises remain a risk, as reported by ACM after the release.
• NAB senior economist Taylor Nugent said ahead of the data that NAB expects inflation to moderate through 2027, with rent inflation cooling.
• ABC business editor Michael Janda said the steady core reading suggests things are "not getting worse". He added that this might let the RBA wait and see for longer.
• Capital.com senior analyst Kyle Rodda argued before the release that another rise is a question of when, not if.

What markets are pricing

Before the release, market pricing implied roughly a 35–45% chance of a November rise, based on figures reported by Capital.com and Finimize. After the softer monthly core reading, the ABC reported that the odds fell to just under 20%, citing LSEG data, and investingLive put them at about 25%. The Australian dollar dipped about 0.2 US cents after the release (ABC). Market pricing changes daily and is not a forecast by IFG.

RBA Governor Michele Bullock indicated this week that the Board will now assess what the rises already made will deliver in the months ahead. The Board has also said it will raise rates again if needed. We explain the September decision in full in our RBA rate decision explainer.

Key Dates That Will Decide the Next Rate Move

How Much Would Another 0.25% Rate Rise Add to My Repayments?

If another 0.25% rise were passed on in full, a 30-year principal-and-interest loan of $500,000 would cost about $83 more a month, and a $750,000 loan about $123 more. This is a scenario, not a prediction. Use it to test whether your budget has enough buffer.

Illustrative only. The table is a hypothetical stress test, not a forecast. It assumes a further 0.25% change passed on in full, applied to an assumed variable rate of 6.50% p.a. rising to 6.75% p.a., on an owner-occupier principal-and-interest loan over 30 years, rounded to the nearest dollar, with fees excluded. Your rate, loan term, balance and outcome will differ.

Separately, the 29 September rise is still flowing through. Lenders are expected to adjust variable rates over the next 14 days following that decision. Exact timing varies by lender, and your lender will notify you.

What Does This Mean for Melbourne Borrowers?

Whatever happens in November, the next few weeks are a good time to prepare. Here's how different borrowers can use them:

• Owner-occupiers: check that your budget can absorb the September rise plus a possible further 0.25%. Compare your rate with what new customers are offered, because a refinancing review can offset some of the increase.
• Buyers with pre-approval: higher rates reduce borrowing power under lenders' serviceability buffers. Re-check your limit with our borrowing power calculator before bidding this spring.
• First home buyers: confirm your scheme eligibility and price caps on our first home buyer loans page.
• Investors: review holding costs and loan structure (see investment loans), and speak with your accountant about tax.
• Fixed-rate borrowers: if your fixed term ends in the next six months, start comparing now rather than accepting the revert rate by default.

IFG's Take

After more than two decades in lending, starting in business banking at NAB in 2003, I've learned not to react to a single month's headline. What mattered in August was that underlying inflation didn't speed up, even as fuel pushed the headline to 4%. That doesn't rule out another rise, and we don't make rate predictions. It does mean October's quarterly figures carry a lot of weight.

The borrowers who handle this period best are the ones who check their position early. We do that every day for clients across Melbourne's north and west, from Essendon and Moonee Ponds to Coburg North. If you'd like a clear view of your own numbers, start at our Melbourne mortgage broker home page.

Frequently Asked Questions: August 2026 CPI and Interest Rates

What was Australia's inflation rate in August 2026?

Headline inflation was 4.0% over the year to August 2026, up from 3.5% in July, according to the ABS. Trimmed mean inflation, the RBA's preferred underlying measure, was 3.6% for a third consecutive month.

Why did inflation rise to 4% in August 2026?

The ABS said housing was the largest contributor, up 5.7%, driven by new dwelling costs and electricity. Transport rose 5.6%, with fuel up 14.8% in the month because of higher world oil prices and the unwinding of fuel excise relief.

Will the RBA raise interest rates in November 2026?

No one can say for certain. Westpac expects another rise, while CBA and NAB forecast a hold with the risk of more rises. Markets cut the odds of a November rise after the August CPI. The September-quarter CPI in late October will be closely watched.

What is trimmed mean inflation?

Trimmed mean inflation removes the largest price rises and falls each period, to show underlying price pressure. The RBA focuses on it because one-off shocks, such as fuel spikes or the end of energy rebates, can distort headline inflation.

When will my home loan rate change after the September rate rise?

Lenders are expected to adjust their variable rates over the next 14 days following the 29 September decision. Timing varies by lender, and your lender will notify you of any change. Fixed rates are unaffected until the fixed term ends.

This article is general information only and does not constitute financial, credit, tax or legal advice. It does not take into account your objectives, financial situation or needs; consider whether it is appropriate for you and seek personalised advice before acting. Inflation data is sourced from the Australian Bureau of Statistics release of 30 September 2026 and may be revised. Economist views and market pricing are those of the parties named, as reported on 30 September 2026, and may change at any time; they are not predictions by Integrated Finance Group. Repayment figures are illustrative only, based on the hypothetical assumptions stated; they are not offers of credit. Integrated Finance Group’s brokers are Credit Representatives of BLSSA Pty Ltd, Australian Credit Licence 391237. All credit applications are subject to lender assessment and approval. Our Credit Guide is available on request. Tax questions should be directed to your accountant.