FIRE Monte Carlo Simulator
Test your FIRE plan with Monte Carlo and rolling historical retirement simulations using stocks, bonds, cash, inflation, and withdrawals.
FIRE Milestone Calculator
Map your progress towards various FIRE milestones including coast FIRE, barista FIRE, lean FIRE, fat FIRE, and more.
Your plan
Spending goals
Advanced assumptions
Projected path
All dollar values are shown in today's dollars.
Milestone details
| Milestone | Target | Progress | Gap | Estimated age |
|---|
Interpret your FIRE milestone estimate
The calculator turns your portfolio, savings rate, spending goals, withdrawal rate, and return assumptions into a milestone map. It estimates where you are today and when each target could be reached if the assumptions hold.
Inputs that matter most
- Current portfolio: invested assets available for financial independence.
- Annual spending: the lifestyle cost each FIRE tier needs to support.
- Monthly investments: ongoing savings that help you reach portfolio targets.
- Withdrawal rate: the annual spending percentage used to translate spending into a portfolio number.
- Real return: investment return after inflation, used for milestone age estimates.
Common mistakes
- Treating FIRE labels as fixed universal definitions.
- Using pre-tax spending when retirement withdrawals will need to cover taxes.
- Ignoring health care, housing changes, college costs, or other large future expenses.
- Assuming a smooth annual return instead of testing the plan with volatile markets.
When this estimate can be misleading
The estimate can be misleading if your future spending, tax rate, asset allocation, side income, or market return differs materially from the assumptions entered.
Scenarios to try
- Lower annual return to test a conservative market case.
- Raise FIRE spending for taxes, health insurance, or travel.
- Change barista income to model part-time work, consulting, or rental income.
- Compare the estimated FIRE age with your target retirement age.
Next-step utilities
How to use this FIRE milestone calculator
Use this calculator when you want a quick map of financial independence milestones instead of a full retirement simulation.
- Enter your age, target retirement age, current portfolio, and monthly investment amount.
- Set annual spending targets for lean FIRE, FIRE, chubby FIRE, and fat FIRE.
- Open advanced assumptions to adjust barista income, withdrawal rate, expected return, and inflation.
- Review your next milestone, gap, estimated age, chart, and milestone table.
- Use the Monte Carlo simulator next if you want to test sequence risk and market volatility.
FIRE Milestone Calculator features
- Calculate coast FIRE using your target retirement age and inflation-adjusted return.
- Estimate barista FIRE from annual spending minus expected flexible income.
- Map lean FIRE, FIRE, chubby FIRE, and fat FIRE portfolio targets.
- Show current progress, remaining gap, and estimated age for each milestone.
- Project portfolio growth from current assets and monthly investments in today's dollars.
- Compare milestone targets in a chart and detailed table.
- Adjust withdrawal rate, investment return, inflation, and spending assumptions.
What FIRE milestones mean
FIRE stands for financial independence, retire early. In practice, people use several milestone labels because financial independence is not a single on-off switch.
Coast FIRE means your invested balance is projected to grow to your FIRE number by the target retirement age without additional retirement contributions from that point forward. It does not mean you can stop working today; it means future retirement saving may no longer be required once the coast milestone is reached.
Barista FIRE means your investments could cover part of your spending while part-time, consulting, seasonal, business, rental, or other flexible income covers the rest. The calculator subtracts the entered annual barista income from your standard FIRE spending, then applies the withdrawal rate to the remaining spending need.
Lean FIRE, FIRE, chubby FIRE, and fat FIRE are lifestyle targets. Lean FIRE usually implies a lower annual spending plan. Chubby FIRE and fat FIRE usually imply more spending room, more travel, higher housing costs, larger tax reserves, or more margin for uncertainty. Because the definitions are personal, this calculator lets you enter the annual spending behind each label.
The milestone names are useful shorthand, but the underlying math matters more than the label. A plan with a realistic spending number, taxes, health care, housing, and market risk is stronger than a plan that only reaches an attractive acronym.
How to sanity-check your FIRE milestone plan
The calculator is most useful when you treat each result as a planning signal, then test whether the assumptions match your real life.
Start with the closest unreached milestone. If the gap is small, look at whether a one-time contribution, a higher monthly investment, or a modest spending reduction would move the date meaningfully. If the gap is large, the more useful question is often which input has the most leverage: savings rate, annual spending, investment return, or target age.
Use the progress cards to compare milestones, but do not read them as a recommended order for your life. Someone with a stable career may care most about standard FIRE or fat FIRE. Someone who wants part-time work or a sabbatical path may care more about barista FIRE. Someone who enjoys their work but wants retirement savings to become optional may care most about coast FIRE.
Run at least three assumption passes before acting on the result: a base case using your current plan, a conservative case with lower returns or higher spending, and an optimistic case that reflects what happens if income, savings, or expenses improve. If the same milestone stays close across all three cases, it is a stronger planning signal than a milestone that only appears in the optimistic case.
Before treating any milestone as reached, check the expenses the calculator does not know: taxes, health insurance, housing changes, dependents, education costs, debt payoff, relocation, large purchases, and emergency reserves. FIRE math is sensitive to missing expenses because annual spending is divided by the withdrawal rate, so every extra $1,000 of yearly spending adds $25,000 to a 4% FIRE target.
FIRE milestone formulas
The calculator converts annual spending goals into portfolio targets, projects portfolio growth, and estimates when each milestone is reached.
F = \frac{S}{w}
S is annual spending and w is the withdrawal rate.
C = \frac{F}{(1+r)^{y}}
F is the standard FIRE number in today's dollars, r is the real return after inflation, and y is years until the target retirement age.
B = \frac{\max(S-I,0)}{w}
I is expected annual flexible income. The target floors at zero if income covers the spending entered.
Portfolio growth is projected monthly in today's dollars using the real return after inflation. Milestone ages are estimates from that smooth projection, so they are best read as planning markers rather than predictions.
Coast FIRE asks whether today's portfolio can grow to the FIRE target by the target retirement age without additional retirement contributions. If that does not happen by the target retirement age, the calculator reports it as not reached by that age.
FIRE milestone calculator FAQ
Which withdrawal rate should I use?
Many FIRE plans start around 4%, but the right assumption depends on retirement length, taxes, fees, asset allocation, flexibility, and risk tolerance. Try 3.0%, 3.5%, and 4.0% to see how sensitive your targets are.
Does coast FIRE mean I can retire now?
No. Coast FIRE means that once the coast milestone is reached, the invested balance may grow to the FIRE number by the target retirement age without more retirement contributions. You still need income for current living expenses until then.
Why can barista FIRE be lower than lean FIRE?
Barista FIRE includes annual flexible income. If that income covers a meaningful share of spending, the portfolio needed to fund the remaining gap can be lower than a no-work lean FIRE target.
Does this include taxes?
No. Enter spending targets that already include expected taxes, insurance, and other retirement costs. For taxable accounts or high-fee portfolios, use a lower return or withdrawal-rate assumption.
What should I enter for annual spending?
Use the amount your portfolio would need to support in retirement, not only today's household budget. Include recurring costs such as housing, groceries, utilities, travel, insurance, taxes, gifts, car replacement, and a reserve for irregular expenses. If you are unsure, run a lean number, a comfortable number, and a high-margin number.
Why can coast FIRE say it is not reached by my target age?
Coast FIRE is tied to the target retirement age. It asks whether the portfolio can grow to the FIRE target by that age without more retirement contributions. If ongoing contributions are still needed to reach the FIRE target, coast FIRE can say not reached by that age even when another milestone has a later estimated age.
How is this different from the FIRE Monte Carlo Simulator?
This calculator is a deterministic milestone map. The Monte Carlo simulator tests retirement outcomes across randomized and historical return sequences, which is better for stress-testing a withdrawal plan.
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