FIRE calculator
Explore a financial-independence target.
- Formula and assumptions shown
- Table and CSV export
- Runs in your browser
How it works
The target starts with annual spending divided by the withdrawal-rate assumption you enter. The modeled target then rises with the entered inflation assumption while current savings and contributions grow month by month.
Initial target = annual spending ÷ withdrawal rate; later target = initial target × (1 + inflation)^(elapsed years).
The withdrawal rate is a planning input, not a promise that a portfolio will last. Adjust return, inflation, contributions, and spending to explore the sensitivity of the result.
Assumptions
- Annual spending and withdrawal rate are entered assumptions; the rate is not presented as safe or guaranteed.
- Return, inflation, and contributions stay constant in the bounded 600-month projection.
- Contributions are added monthly after return is applied; the target rises with the entered inflation assumption.
- Taxes, benefits, fees, market volatility, and a safety judgment about the withdrawal rate are excluded.
Worked example
$40,000 annual expenses at a 4% assumption
The target today is $40,000 ÷ 0.04 = $1,000,000. Starting from $0 and contributing $10,000 monthly at 0% return and 0% inflation reaches that target in 100 months.
Step by step
- Target today. $40,000 of annual expenses ÷ 4% = $40,000 ÷ 0.04 = $1,000,000.
- Target over time. With 0% inflation, the target stays at $1,000,000 in every month instead of rising.
- Savings growth. At a 0% return, the balance grows only by the $10,000 monthly contribution, so after m months it is $10,000 × m.
- Time to target. $1,000,000 ÷ $10,000 = 100 months (8 years 4 months), when the projected balance equals the $1,000,000 target.
How to read your result
FIRE target today is annual expenses divided by the withdrawal rate, in today’s dollars. Time to inflation-adjusted target is the first month the savings balance reaches the target after the target has been raised for inflation. Projected balance is the savings at that month and Target at horizon is the inflated target it had to meet; with the defaults, $1,500,000 today becomes $3,501,686.84 by month 412. Assumed withdrawal rate repeats the rate you entered.
The chart plots savings against the rising target, and the point where the lines meet is the result. The monthly table lists both. Because the target grows with inflation, what drives the timeline is the gap between the return and inflation, not the return alone.
Taxes are not modeled, so annual expenses need to include any tax due on withdrawals, and health insurance before Medicare eligibility can be a large item for early retirees. Social Security and other income are not counted, which makes the target larger than it would be if that income were subtracted from expenses. The result stops at the month the target is reached and says nothing about how long the money lasts afterward; the retirement withdrawal calculator tests that.
What changes the result most
- Withdrawal rate
- With the defaults ($60,000 expenses, $100,000 saved, $2,000 a month, 6% return, 2.5% inflation), a 4% rate gives a $1,500,000 target reached in 412 months (34 years 4 months). At 3.5% the target is $1,714,285.71 and takes 451 months.
- Annual expenses
- Spending $50,000 instead of $60,000 lowers the target to $1,250,000 and the time to 362 months. The target moves in direct proportion to expenses.
- Monthly contribution
- Saving $3,000 a month instead of $2,000 reaches the target in 324 months, 88 months sooner.
- Return and inflation
- A 7% return shortens the timeline to 353 months. Setting inflation to 0% with the 6% return shortens it to 268 months, because the target no longer rises.
Questions
Is 4% a guaranteed safe withdrawal rate?
No. The calculator does not endorse any rate. It treats your chosen percentage as a scenario input and cannot account for every future market or spending path.
Should I use current or future spending?
Use the spending amount that matches the scenario you want to test, and use inflation assumptions when comparing future dollars with today's spending.
Does FIRE mean I can stop working?
The result is only a mathematical target and timeline. Employment, health, taxes, insurance, and personal choices remain outside the model.
What is a FIRE number?
In the financial independence, retire early (FIRE) community, the FIRE number is the portfolio size at which planned withdrawals could cover annual spending. It is usually estimated as annual expenses divided by a withdrawal rate, which is the same as expenses times 25 at 4% or about 28.6 at 3.5%. It is a planning estimate that depends on the rate chosen, not a guarantee that the money will last.
What is the 4 percent rule?
The 4 percent rule is a guideline from research on historical U.S. market returns, starting with William Bengen’s 1994 study: withdrawing 4% of a portfolio in the first year of retirement and raising that amount with inflation each year would have lasted at least 30 years in the periods tested. Early retirements can last much longer than 30 years, and past returns may not repeat, which is why some people test lower rates. This calculator lets you enter any rate.
How much do I need to retire early?
The FIRE target is a starting point: annual expenses divided by a withdrawal rate. At $60,000 of expenses and a 4% rate that is $1,500,000 in today’s dollars. Retiring early usually adds costs a standard retirement estimate may leave out, such as health insurance before Medicare, taxes on withdrawals, and more years for the money to last, plus limits on reaching some retirement accounts before age 59½ without penalty.
More in Retirement
Sources
These references explain the concepts behind the calculation. They do not endorse this site. Estimates leave out any cost or condition you did not enter.