FIRE Number Mistakes Australians Make and How to Avoid Them

Updated 7 July 2026 · Super and retirement

A FIRE Number Calculator gives a fast answer, but the answer is only as good as what goes in. These are the mistakes we see most often with FIRE number calculations in Australia, and how to avoid them.

1. Leaving multiple accounts open

Each account charges fees and may carry insurance premiums. Consolidating through myGov is usually quick.

2. Ignoring fees

A fee difference of 1% a year looks tiny but can reduce a balance by six figures over a working life.

3. Going over the contribution caps

Excess concessional contributions are taxed at your marginal rate, and the cap includes your employer’s contributions.

4. Not checking your employer pays super

Check your fund statements or myGov to confirm contributions arrive. Unpaid super can be reported to the ATO.

5. Overlooking the detail that matters most here

Australians can’t access super before preservation age, so early retirees need enough outside super to bridge the gap.

How the FIRE number changes with safe withdrawal rate

A common mistake is getting one input slightly wrong. Here is what happens to the FIRE number when “Safe withdrawal rate (%)” is off by up to 20% in either direction, with everything else held steady.

Safe withdrawal rate (%)	FIRE number
3	$1,666,666.67
4	$1,250,000.00
5	$1,000,000.00

At 3 the result is $1,666,666.67; at 5 it is $1,000,000.00. If a small change in this input moves the answer a lot, it is worth double-checking that figure before you rely on the result.

A quick sense check

FIRE number = annual expenses ÷ withdrawal rate. At 4% that is 25 times your spending. With typical inputs the calculator returns FIRE number of $1,250,000.00. If your own result looks wildly different, check that each figure is in the right unit and period (weekly, monthly or yearly) before drawing conclusions.