Freedom CalcsFinancial independence, with clear assumptions
FIRE Number Calculator
Translate the spending your investments must cover into a portfolio target. This is a spending-to-assets calculation, without a future-growth timeline.
Example estimate
- FIRE number
- $1,250,000
- Annual portfolio-funded spending
- $50,000
- Gap from current assets
- $1,150,000
This is a target in today’s dollars. It does not forecast growth, a retirement age, or the probability of a successful retirement.
| Assumption | Portfolio target |
|---|---|
| 3% withdrawal | $1,666,667 |
| 3.5% withdrawal | $1,428,571 |
| 4% withdrawal | $1,250,000 |
| 4.5% withdrawal | $1,111,111 |
| 5% withdrawal | $1,000,000 |
Educational estimate. Taxes, fees, market volatility, account access, and later retirement withdrawals are not simulated.
How this calculator works
FIRE number = max(annual spending − continuing annual income, 0) ÷ withdrawal rate
This is a deterministic illustration. The withdrawal rate sets a target, without simulating later withdrawals or estimating a safe rate. Dollar displays are rounded; calculations retain precision.
Reproduce the default example
$50,000 annual spending, no continuing income, a 4% withdrawal assumption, and $100,000 invested assets. All amounts are today’s USD. These are hypothetical inputs, not a recommended budget or return forecast.
- Portfolio-funded spending = max($50,000 − $0, 0) = $50,000 per year.
- Target = $50,000 ÷ 0.04 = $1,250,000.
- Current-assets gap = max($1,250,000 − $100,000, 0) = $1,150,000. No future growth is assumed.
| Withdrawal assumption | Portfolio target |
|---|---|
| 3% | $1,666,667 |
| 4% | $1,250,000 |
| 5% | $1,000,000 |
This fixed example stays separate from your live results above. Sensitivity comparisons change one assumption at a time and show model arithmetic, not historical outcomes or the chance of retirement success.
What does a FIRE number mean?
Your FIRE number is a portfolio target derived from the annual spending that investments need to fund. FIRE stands for financial independence, retire early. Reaching this number under one assumption does not establish that you can retire safely or that every year of spending is covered.
Subtract income only when it is available throughout the period you are modeling and uses the same purchasing-power convention. The calculator does not decide when a pension or benefit starts. Temporary income or a future benefit needs a timeline model rather than a simple subtraction today.
The 25-times-spending shortcut
Dividing by 4% is equivalent to multiplying annual portfolio-funded spending by 25. For $50,000 spending and no other income, the target is $1,250,000. At 3%, it is $1,666,667 after rounding; at 5%, it is $1,000,000.
With $10,000 of continuing income, the portfolio-funded spending falls to $40,000 and the 4% target becomes $1,000,000. If income equals or exceeds expenses, the arithmetic target is zero. That output says nothing about the security or longevity of the income stream.
A withdrawal assumption is not a guarantee
The withdrawal rate here means first-year annual spending divided by the initial target portfolio. Historical withdrawal research explored specific portfolios, periods, and spending rules. It is not a promise that taking the same percentage of your current balance each year will fund fixed purchasing-power spending.
This tool does not estimate the chance of running out of money. Longer retirements, taxes, fees, future market returns, and the order of returns can change outcomes. Compare several withdrawal assumptions and examine the underlying research before using the target in a real plan.
Choose the right follow-up calculation
Use the Coast FIRE Calculator to discount a future retirement target into a savings milestone today. Use Fat FIRE or Lean FIRE to build a budget and project an accumulation path. Use Barista FIRE when work income supplements withdrawals for a limited period.
Your current-assets gap on this page is simply max(target − assets, 0). It does not include future growth or contributions. Keeping that distinction visible helps avoid treating a target calculation as a retirement timeline.
FIRE Number questions
Comparing tools? Read the FAQs for all five FIRE calculators for help choosing a model and keeping inputs consistent.
Does this calculator predict my retirement age?
No. It returns a spending-based portfolio target and the gap from your current assets. The Fat and Lean tools add accumulation timelines.
Should I enter annual or monthly spending?
Enter annual amounts. Multiply a monthly budget by 12, then add irregular annual costs without counting them twice.
Is the FIRE number in future dollars?
No. Inputs and outputs use today’s USD. This page has no growth or inflation forecast; other income must use the same purchasing-power basis.
Sources, limits, and maintenance
The formulas above are disclosed model arithmetic. Historical withdrawal studies provide context for the initial withdrawal assumption; they do not validate this calculator’s targets, predict future returns, or endorse our work.
- William P. Bengen: Determining Withdrawal Rates Using Historical Data (1994)
Historical withdrawal research; no guarantee for this model.
- Cooley, Hubbard & Walz: Retirement Savings (1998), author-hosted copy
Historical US stocks/corporate bonds, 1926–1995, 15–30-year payouts; excludes taxes and transaction costs.
- US Bureau of Labor Statistics: CPI questions and answers
Population inflation measure; individual spending can differ. This page has no inflation forecast; spending and continuing income must already use the same purchasing-power basis.
The tool does not calculate taxes, benefits, account restrictions, fees, lifespan, or market risk. Include relevant expenses in your budget. Read the shared methodology and financial disclaimer.
How the arithmetic is checked
Tests check spending minus continuing income, withdrawal-rate division, and income equal to or above spending. The repeatable example and sensitivity table are checked against the interactive calculation. These are software and arithmetic checks, separate from financial professional review.
Prepared by Freedom Calcs team. Model version 1.1.0 · Prepared and checked . Send a correction with this page URL, non-sensitive sample inputs, and the result you expected.