How Inflation Affects Interest Rates in Australia

If you've ever wondered why your variable mortgage rate moves shortly after the news reports on inflation, this is why: the Reserve Bank of Australia uses interest rates as its main tool to control inflation, and your home loan rate is directly downstream of that decision. Understanding the link helps you anticipate rate movements instead of just reacting to them.

What is inflation?

Inflation is the rate at which prices for everyday goods and services rise over time, which in turn erodes the purchasing power of your money. Australia's Reserve Bank targets inflation of 2–3% per year, on average, over time — low enough for prices to stay stable, but not so low that the economy stalls.

When inflation runs hotter than that target — as it did through 2022 and 2023 — the RBA responds using the one lever it controls directly: the cash rate.

The RBA and the cash rate

The cash rate is the interest rate the RBA charges banks for overnight loans between themselves. It doesn't sound like it should matter to your mortgage, but banks price nearly all of their lending — including variable home loan rates — relative to it. When the RBA lifts the cash rate, banks' own borrowing costs rise, and they pass most of that increase on to borrowers. When the RBA cuts it, the reverse happens.

The RBA board meets eight times a year to decide whether to move the cash rate, hold it, and by how much — usually in increments of 0.25%.

How inflation affects interest rates

Higher interest rates make borrowing more expensive and saving more attractive, which cools spending across the economy. Less spending means less demand for goods and services, which takes pressure off prices — bringing inflation back down over time. It's a deliberate, blunt tool: the RBA raises rates specifically to slow the economy down when inflation is too high, accepting that mortgage holders and businesses will feel the pinch in the short term.

The relationship also runs in reverse. When inflation falls back within target and economic growth slows too much, the RBA can cut the cash rate to encourage borrowing and spending again — which is typically when variable mortgage rates start coming back down.

How inflation is measured

The Australian Bureau of Statistics measures inflation through the Consumer Price Index (CPI) — tracking the change in price of a fixed basket of goods and services (housing, food, transport, health, education and more) that a typical household buys. The CPI is published quarterly, and the RBA also watches a "trimmed mean" measure of underlying inflation, which strips out the most extreme price swings to see the more persistent trend.

What it means for your mortgage

If you're on a variable rate, cash rate moves flow through to your repayments directly, usually within a few weeks of an RBA decision. If you're on a fixed rate, you're insulated until your fixed term ends — at which point you'll roll onto whatever variable rate (or new fixed rate) applies at that time, which can come as a shock if rates have risen significantly since you fixed.

This is also where the comparison rate matters: it bundles in most fees to show the loan's true annual cost, which becomes more important to check carefully in a rising-rate environment when every fraction of a percent compounds over the life of the loan.

Inflation and credit cards

Credit card interest tends to move in the same direction as the cash rate, though card issuers have more discretion than mortgage lenders and don't always pass on cuts as quickly as they pass on rises. Credit card interest is also calculated daily and compounds if you carry a balance, which is why it climbs faster than a mortgage in a high-rate environment — all the more reason to prioritise paying down card debt before extra mortgage repayments when rates are elevated.

Protecting yourself from rate rises

A few practical steps make a real difference when rates are rising:

• Build a buffer in an offset account so rate rises have less to bite into
• Consider splitting your loan between fixed and variable to spread the risk
• Review your rate against the market periodically — refinancing to a more competitive rate is often the single biggest lever available to an existing homeowner
• Avoid carrying credit card debt, which is the most expensive form of borrowing to hold through a high-rate cycle

What this means for essential workers

Rate cycles affect everyone's borrowing power, but essential workers already have an edge in managing them: specialist lending policies that count 100% of overtime and shift allowances as income give you more headroom to absorb a rate rise than a standard bank assessment would. If rising rates have you reassessing your budget or considering a switch, our Dollars & Sense comparison breaks down exactly how essential worker lending policies compare to standard bank terms.

Frequently asked questions