Retirement / FIRE Number Calculator
Estimate the corpus you need to retire early (or on time), inflation-adjusted, in five flavors of FIRE.
Your FIRE Number
$48,107,032
by age 50
Years to FIRE
20
Years in Retirement
35
Your Expense Timeline
Monthly Expense Today
$50,000
Monthly Expense at Age 50
$160,357
Years to FIRE
20
Years in Retirement
35
Your FIRE Numbers
Coast FIRE
$4,987,100
What you'd need saved today to "coast" — no more contributions — to your FIRE number by your target age.
Lean FIRE
$33,674,922
A leaner corpus, sized to a trimmed-down, minimalist lifestyle.
Barista FIRE
$24,053,516
A smaller corpus, sized to the gap left after part-time work, freelancing, rent, or other extra income covers the rest of your expenses.
Full FIRE
$48,107,032
Corpus to sustain your current lifestyle, unchanged, in retirement.
Fat FIRE
$72,160,548
A larger corpus, sized to an expanded, more comfortable lifestyle.
Track Your FIRE Number
Closing the gap to your FIRE number needs an estimated monthly SIP of $38,494 over the next 20 years, at your expected pre-FIRE return. Model it precisely with:
Frequently Asked Questions
How the Numbers Are Calculated
Today's monthly expenses are inflated forward to your target FIRE age, then each FIRE variant sizes a corpus off that future annual expense using your safe withdrawal rate (SWR) — the same "25x expenses" logic behind the standard 4% rule.
Annual expense at FIRE
Expense(FIRE) = Monthly Expense × 12 × (1 + Inflation)^(FIRE Age − Current Age)
Full / Lean / Fat / Barista FIRE
Corpus = Expense(FIRE) × Lifestyle Ratio ÷ SWR
Coast FIRE
Coast FIRE = Full FIRE ÷ (1 + Pre-FIRE Return)^(FIRE Age − Current Age)
Required monthly SIP
Shortfall = Full FIRE − (Current Savings compounded to FIRE Age); solved for the monthly SIP that grows to Shortfall
- Lean FIRE uses 70% of Full FIRE's expense figure; Fat FIRE uses 150%; Barista FIRE uses (100% − Part-Time / Other Income Coverage%).
- The required monthly SIP uses the same annuity-due formula as the SIP calculator (contributions at the start of each month), solved for the contribution instead of the future value.
- All figures are estimates that assume constant inflation and return rates for the entire horizon; they are rounded only at the point they are displayed.