Inflation

Inflation is the general rise in prices across an economy over time, measured in Australia by the Consumer Price Index, or CPI, which the Australian Bureau of Statistics publishes quarterly. When inflation runs at 3 percent, a $100 basket of groceries costs $103 a year later, and your salary buys 3 percent less of everything. The Reserve Bank targets inflation between 2 and 3 percent, which is the band every interest rate decision in Australia is calibrated against.

Inflation matters to investing because it silently adjusts every return. A savings account paying 4 percent while inflation runs at 3 percent is earning a real return of roughly 1 percent - the purchasing-power gain is the headline number minus the price rise, not the rate the bank advertises. Cash that earns nothing loses purchasing power every year by definition. The same logic applies to your HECS debt, which is indexed to CPI each June - the 2023 print hit 7.1 percent, and every HELP balance grew with it.

The CPI works by pricing a fixed basket of goods and services - housing, food, transport, healthcare and the rest - and comparing the cost to the same basket a year earlier. The inflation rate is one line of arithmetic: the percentage change in the index over twelve months. The ABS publishes the headline figure quarterly, and the RBA also watches the trimmed mean, its preferred core measure that strips out the largest price moves in each direction.

The purchasing-power arithmetic is where investing decisions live. If inflation runs at 3 percent, the purchasing power of a fixed cash balance divides by 1.03 every year: $10,000 held for a decade at 3 percent inflation has the buying power of roughly $7,440 in today's dollars. A savings account partially offsets this: $10,000 at 4.5 percent for ten years grows to about $15,530 nominally. That is roughly $11,560 in today's purchasing power - a real gain, but far smaller than the headline number suggests.

This is also why the RBA raises the cash rate when inflation runs hot: higher rates make borrowing expensive and saving attractive, which cools demand and pulls prices back toward the band. You can run your own purchasing-power numbers through the inflation calculator.

Every financial decision in Australia runs through inflation whether you notice it or not. Your savings account's advertised rate is a nominal number. Your mortgage's rate interacts with the RBA's inflation-fighting, your super's long-run return only counts in real terms, and your HECS balance is indexed to the same CPI print every June. A retirement plan modelled on nominal returns without an inflation haircut is a plan built on the wrong currency.

I have watched a colleague named Brent (yes, that Brent) leave $15,000 in a transaction account paying nothing for three years because 'savings accounts are not worth the hassle'. At 3 percent inflation, that inaction cost him roughly $1,300 of purchasing power - a fee nobody charged him, for a service nobody provided. The highest-leverage thing most Australians can do is check the real return on every cash balance - the advertised rate minus inflation, run it through the inflation calculator - and never model a long-term plan without the inflation haircut.