Interactive financial calculator
FIRE Number Calculator
A FIRE number is an illustrative portfolio target based on annual expenses and a chosen withdrawal rate.
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Methodology & Assumptions
How this estimate is calculated
Formula: (Annual Expenses − Expected Other Income) ÷ Withdrawal Rate. The other-income field defaults to $0, which reproduces the standard Annual Expenses ÷ Withdrawal Rate result exactly. Informed by Cooley, Hubbard, and Walz's historical withdrawal-rate research. The 4% default is an illustrative rule for a 30-year horizon, not a guarantee. The return input is treated as real (after inflation). Expected Other Income should be an annual, after-tax (spendable) amount in today's dollars — not a monthly figure. Any entered other income is treated as available from the very first year of the modeled retirement, not phased in at a later claiming or start age, and as holding its value in today's dollars for the entire retirement; a fixed (non-COLA) benefit entered this way can overstate its real purchasing power over a long retirement.
Illustrative result: figures are rounded for display after calculations use full numeric precision. Actual results may differ.
Currency: dollar symbols are a display convention. Enter every monetary amount in one consistent currency; the calculator does not convert currencies or apply jurisdiction-specific tax rules.
What Is a FIRE Number?
A FIRE number is an estimated invested portfolio target intended to support withdrawals for living expenses. The term comes from the FIRE movement: Financial Independence, Retire Early. Actual sustainability depends on returns, inflation, fees, taxes, spending flexibility, and the retirement horizon.
The most widely used formula is the 25x rule, derived directly from the 4% safe withdrawal rate:
FIRE Number = Annual Expenses × 25
If you spend $50,000/year, the 25x rule produces a $1,250,000 illustrative target. Four percent of that starting portfolio equals $50,000 in year one; it does not ensure returns will cover every future withdrawal.
FIRE Numbers by Annual Spending
| Annual Spending | 4% Rule (25x) | 3.5% Rule (28.6x) | 3% Rule (33.3x) |
|---|---|---|---|
| $30,000 | $750,000 | $857,000 | $1,000,000 |
| $50,000 | $1,250,000 | $1,429,000 | $1,667,000 |
| $60,000 | $1,500,000 | $1,714,000 | $2,000,000 |
| $80,000 | $2,000,000 | $2,286,000 | $2,667,000 |
| $100,000 | $2,500,000 | $2,857,000 | $3,333,000 |
Each cell is annual spending ÷ withdrawal rate, rounded to the nearest $1,000. The 28.6x and 33.3x multipliers are themselves rounded (exact values are 100/3.5 and 100/3).
A 3.5% or 3% withdrawal rate produces a larger target than 4% for the same spending, which some savers choose to test for a longer expected retirement horizon. Neither rate, nor any other, is validated by this calculator against portfolio survival probability — no rate is a guarantee, and the choice of rate is a personal stress test, not a formula tied to a specific age.
How to Use This Calculator
Enter your annual expenses and adjust the withdrawal rate slider to match your retirement timeline. The calculator instantly shows your FIRE number, current gap, and estimated time to reach financial independence based on your current savings and monthly contributions.
If you choose to copy a scenario link, the selected inputs are included in the URL. Use the separate clean share action when you do not want to include financial values.
Two Levers That Move Your FIRE Number
Reduce expenses. Every $100/month cut from spending reduces your FIRE number by $30,000 at the 4% withdrawal rate. Lower spending simultaneously reduces the target and increases monthly savings — the most powerful lever available.
Adjust withdrawal rate. Dropping from 4% to 3.5% increases the target by about 14%. A lower initial withdrawal may provide more room for uncertainty, but this calculator does not model portfolio survival.
Related: Calculate your Coast FIRE number — the amount needed to stop saving and let compound growth carry you to retirement.
Modeling Pension, Social Security, or Part-Time Income
If you expect reliable income once retired — a pension, Social Security, part-time work (sometimes called "Barista FIRE"), or net rental income — enter it in the optional Expected other income field as an annual, after-tax (spendable) amount in today's dollars, not a monthly figure. The calculator subtracts it from your annual expenses first, so your FIRE number reflects only the spending your portfolio needs to fund. Leaving it blank or at $0 produces the standard, income-free FIRE number.
This is a simple same-year offset, not a timeline: it assumes the entered income is already available for your entire modeled retirement and holds its value in today's dollars throughout. See the FAQ below for how to handle income that actually starts years after you retire, and the FIRE Number with Pension or Other Retirement Income guide for a worked adjusted-target example and bridge-period planning guidance.
Frequently Asked Questions
Is the 4% rule still useful?
It remains a commonly discussed historical planning framework, not a forecast. Outcomes depend on retirement length, asset allocation, fees, taxes, market sequence, and spending flexibility. Test other rates and review the limitations before using it as one input to a plan.
Should I include home equity in my FIRE number?
No — count only liquid, investable assets. Your primary residence is not a retirement income source unless you sell and downsize. Home equity is worth tracking in your net worth, but your FIRE number should reflect only portfolio assets that generate returns.
What if I have Social Security or a pension?
Enter it in the Expected other income field above as an annual, after-tax amount in today's dollars — the calculator subtracts it from your annual expenses before applying the withdrawal rate. That field treats the entered amount as available from the very first year of retirement and as holding its value in today's dollars for the whole retirement; a fixed (non-COLA) benefit entered this way can overstate its real purchasing power over time. If a pension or Social Security benefit actually starts years after you retire, that gap is a bridge period this field does not model: treat the bridge years as needing 100% portfolio-funded spending on their own, and use your personalized SSA benefit estimate rather than a national average. This FIRE Number field remains a simple same-year offset and does not itself model a delayed start. For one continuous month-by-month projection that covers the bridge years and a later-starting benefit together, use the optional recurring-income start age on the Retirement Withdrawal Calculator. See the FIRE Number with Pension or Other Retirement Income guide for a worked adjusted-target example and bridge-period planning guidance. Eligibility, tax treatment, and start dates vary by program and country.
How does inflation affect my FIRE number?
The 4% rule already accounts for inflation — it assumes you increase withdrawals by the inflation rate each year. Calculate your FIRE number using today's dollars; the withdrawal mechanism handles future inflation automatically. Use our inflation calculator to see how inflation erodes purchasing power over time.
Can I retire before reaching my full FIRE number?
Retiring before your full FIRE number changes the underlying assumptions and risks — your portfolio has less cushion for market downturns, unplanned spending, or a longer-than-expected retirement. Part-time work, consulting, rental income, or other recurring income (sometimes called "Barista FIRE" or semi-retirement) can reduce the portion of annual spending your portfolio needs to fund. If that income is reliably available from the very first year of retirement, you can model it with the Expected other income field above. Doing so does not prove you are ready to retire or guarantee your plan is sustainable — it only shows the portfolio-funded target under that assumption. For a dedicated full-FIRE-vs-reduced-target comparison, see the Barista FIRE Calculator.