Your Number
Your FIRE number isn't a single lump sum — it's the point where your income sources cover your life. Read how it's defined, then calculate where you stand.
The 15% buffer above expenses absorbs what a bare break-even number doesn't: unexpected costs, inflation drift between recalculations, and bad years without forcing a lifestyle cut.
Step 1Find your annual expenses
Not your income — your spending. Pull 3–6 months of real numbers if you can, then annualize. Include:
- Housing (rent or mortgage, property tax, insurance, maintenance)
- Food, transportation, utilities
- Healthcare and insurance premiums
- Discretionary spending (travel, hobbies, gifts)
- One-time or irregular costs, averaged out (car replacement, home repairs)
Retirement spending often shifts — commuting costs drop, healthcare costs rise, travel and hobby spending often increases. Adjust rather than using today's number as-is.
Step 2Add up guaranteed income
Income that arrives regardless of market performance:
- Pension payments
- Social Security (or equivalent) — at your planned claiming age, not today's estimate
- Rental income under a long-term lease
- Annuity payouts
- Any other contractual, non-market-dependent income
Step 3Estimate expected investment income
A rough estimate: portfolio balance × expected annual return rate. This is a simplification — it ignores sequencing and year-to-year volatility — but it's a reasonable planning proxy, and it's the number you control most directly through how much you save, invest, and how your balance grows.
Step 4Check coverage
Guaranteed income + investment income ≥ 1.15 × annual expenses.
If you're under 115%, the gap tells you exactly what to close — earn more guaranteed income, grow the portfolio, or trim expenses.
Step 5Adjust for your FIRE flavor
| Type | Definition |
|---|---|
| Lean FIRE | Minimalist expenses, smaller gap to close |
| Fat FIRE | Higher spending, larger income target |
| Coast FIRE | Guaranteed income alone is projected to cover a large share, so current savings just need to grow untouched |
| Barista FIRE | Part-time income fills part of the guaranteed-income role |
Worked example
$37,200/yr ÷ 6% gets to the $620,000 balance needed to produce it. Change the return assumption and the required balance moves — a higher rate needs a smaller portfolio, a lower rate needs a bigger one.