- Enter the annual budget you expect to maintain after leaving full-time work.
- Select the initial withdrawal rate.
- Add your current portfolio, annual contribution, and return assumption.
- Check whether the lean target leaves enough room for irregular costs.
Lean FIRE Calculator
Build a financial independence target around a deliberately lean annual budget. Beyond the basic spending multiple, this calculator shows the monthly budget, current funding progress, and an estimated time to close the gap with continued investing.
Planning assumptions
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Result
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Lean FIRE portfolio target
Lean monthly budget—
Current progress—
Remaining amount—
Estimated years—
Lean FIRE target = Lean annual budget ÷ Withdrawal rate
What the result means
This is the invested portfolio associated with the entered low-cost lifestyle. It should be tested against housing, healthcare, taxes, repairs, and other uneven expenses.
A lean target offers less room for spending surprises. Consider maintaining a separate cash reserve and testing a higher expense scenario.
A $36,000 annual budget at a 4% withdrawal rate produces a $900,000 Lean FIRE target and a $3,000 monthly spending plan.
How much is needed for Lean FIRE on $3,000 per month?
That is $36,000 per year; at a 4% withdrawal rate the portfolio target is $900,000.
Should health insurance be included in a Lean FIRE budget?
Yes. Include premiums, deductibles, and expected out-of-pocket costs in the annual budget.
Can housing costs be excluded after a mortgage is paid off?
The mortgage payment may end, but property tax, insurance, maintenance, utilities, and repairs should remain in the budget.
Why does the calculator show an estimated timeline?
It compounds the current portfolio and adds annual contributions to show how long the entered assumptions take to reach the target.
Is Lean FIRE the same as a minimum emergency budget?
No. The entered budget should represent a sustainable long-term lifestyle rather than a temporary crisis-level spending plan.