Fire Calculator
FIRE planning centers on the relationship between spending, savings rate, and investable growth. This tool frames independence as a modeled outcome: whether your trajectory supports your target spend with the return and inflation assumptions you believe are realistic — not the most optimistic forum headline.
Quick answer
Set lean spending targets, contribution paths, and return assumptions. Review years-to-goal and readiness — then stress returns to see if the FI timeline is robust or lucky.
For a related estimate, see Early Retirement Calculator.
Explore further: How Long Will My Money Last · How Much Do I Need To Retire
How to use this calculator
- Separate lean-FI from lifestyle-FI: The same math with different spending targets yields very different asset needs.
- Anchor ages and horizon: Current age, retirement age, and how long the portfolio must fund spending drive every output.
- Separate real from nominal: Inflation pairs with spending growth; real return pairs with long-run sustainability.
- Use Advanced mode when taxes differ by account: Roth, traditional, and taxable buckets change spendable cash even when totals look equal.
What FIRE math rewards
High savings rates and expense control move timelines more reliably than small return bumps.
Explore further: Retirement At 40 · Retirement At 50
FIRE vs generic early retirement
FIRE emphasizes expense discipline and savings intensity; early retirement pages focus on timeline mechanics. Both use the same engine with different emphasis.
Real-world example
- Example: raise savings 5% of income: Small savings increases can materially shorten time-to-target when compounded — the charts show contribution vs growth (illustrative).
Explore further: Retirement At 60 · Retirement Calculator
If the FI date is uncomfortably far
Cut fixed costs, increase earnings, or accept a higher working horizon — chasing return alone is fragile.
FAQ
Is readiness a guarantee?
No. It is a modeled score from your inputs. Use it to prioritize savings, timeline, and spending tradeoffs.
Should I trust one Monte Carlo run?
Use it as a stress lens. If success is high but fragile to small return cuts, widen your cushion.
Does this replace personalized advice?
No — especially for tax, healthcare, and estate complexity.