Fat FIRE Calculator — Australia

At Fat FIRE incomes, most savings cannot go into super at the concessional rate. The concessional cap is $32,500 in 2026-27, and it includes your employer's Super Guarantee (ATO). On the default salary of $260,000, the Super Guarantee alone is $31,200, leaving $1,300 of room for salary sacrifice.

Above the cap, savings go outside super after tax at your marginal rate. After-tax (non-concessional) contributions to super are capped at $130,000 a year, four times the concessional cap, and are only allowed while your total super balance is under the general transfer balance cap (ATO). The calculator does not model them.

Division 293 also applies once income plus concessional contributions passes $250,000: a further 15% on the lesser of those contributions and the amount over the threshold (ATO). The calculator applies it each year.

From 1 July 2026, Division 296 taxes the earnings on the part of a person's total super balance above $3 million at 30% in total, and above $10 million at 40%, instead of 15%. The calculator does not model it, so for balances heading past $3 million it overstates growth in super. Most Fat FIRE plans that retire early hold the bulk of their wealth outside super anyway, for the reasons above.

Because the caps bind, a Fat FIRE portfolio is mostly shares, ETFs, property or business assets held personally, through a company or through a trust. Two features of Australian tax shape how that money grows and is drawn down: the 50% capital gains discount on assets held for more than 12 months (ATO), and franking credits on Australian share dividends.

The calculator's default tax drag outside super is 0%, on the basis that franking credits offset most of the tax on Australian dividends, and its default tax on withdrawals is 0%. At Fat FIRE spending, realised gains can reach the higher brackets, so raising the withdrawal tax rate under Assumptions gives a more conservative projection. The calculator does not model companies, trusts or capital gains cost bases.

A Fat FIRE budget carries a lot of spending that could be trimmed in a bad year: travel, renovations, upgrades. That flexibility is worth a great deal. The 4% rule assumes spending never changes; a plan willing to cut, say, 10% after a large market fall can usually sustain a higher starting rate, or the same rate with far less risk.

The drawdown simulator models this with its guardrails rule. Running a Fat FIRE portfolio through it with fixed spending, then with guardrails, shows how much the flexibility is worth on your figures.

With most of the money outside super, high earners rarely fail the bridge test. The challenge is the size of the target: $160,000 a year at a 4% withdrawal rate is about $4 million.

At that scale, small percentages are large amounts. Each 0.1% of fees on $4 million is $4,000 a year, and the "What actually moves your date" panel shows how many years a fee or return difference is worth on your figures.