Retirement & FIRE Calculator
Find your number and when you could reach it.
Yearly spending in retirement, in today's money.
The classic 4% rule gives a 25× target. Long early-retirement horizons often use 3.0–3.5%.
Amount invested each year.
Expected return after inflation. Can be negative.
FIRE number
- Years to reach it
- 22 years
- Projected balance at FIRE
- $1,062,630.36
The FIRE number is your annual expenses divided by your safe withdrawal rate. Years are projected in today's money using a real (inflation-adjusted) return, with contributions added at each year's end.
How the FIRE calculator works
The calculator answers two questions. First, how large a portfolio do you need? That is your FIRE number, and it equals fireNumber = annualExpenses / swr, where SWR is your safe withdrawal rate as a decimal. At the default 4% rate (swr = 0.04), the formula reduces to 25 times your annual spending.
Second, how long until you get there? The tool projects your current balance forward one year at a time using a real (inflation-adjusted) return. Each step it grows the balance, then adds your annual contribution at the end of the year: balance = balance * (1 + r) + contribution. It stops at the first whole year the balance reaches the FIRE number and reports that year along with the balance at that point. Because the return is real, every figure stays in today’s dollars.
Worked example
Inputs:
- Annual expenses: 60,000
- Safe withdrawal rate: 4% (0.04)
- Current savings: 150,000
- Annual contribution: 30,000
- Real return: 5%
Step 1, the FIRE number. 60,000 / 0.04 = 1,500,000. You need a portfolio of 1.5 million.
Step 2, the projection. Start at 150,000. Each year, multiply by 1.05, then add 30,000:
| End of year | Balance |
|---|---|
| 1 | 187,500.00 |
| 10 | 621,670.97 |
| 21 | 1,489,471.94 |
| 22 | 1,593,945.54 |
Year 21 ends just below the target. Year 22 is the first to cross 1.5 million, so the result is 22 years to FIRE, with a projected balance of 1,593,945.54 at that point.
How to use it
- Enter annual expenses, not income. Estimate what you will actually spend in retirement, including healthcare and one-off costs spread out.
- Set the SWR to match your horizon. Use 4% for a roughly 30-year retirement; drop toward 3.0% to 3.5% if you plan to retire early and draw for decades.
- Enter a real return, not a nominal one. A common assumption for a stock-heavy portfolio is 4% to 5% real. Be conservative if you hold bonds or cash.
- Treat annual contribution as new money invested per year. The tool adds it at year end, after that year’s growth.
- Change one input at a time to see its effect. Raising the contribution shortens the timeline far more than small tweaks to the return.
Limitations
This is a smooth, single-rate projection, so it does not capture real market behavior. It assumes a constant real return every year, while actual returns swing and the order of good and bad years matters (sequence-of-returns risk), especially in early retirement. It ignores taxes, fees, account types, changing contributions, lumpy expenses, and guaranteed income such as Social Security or a pension. The 4% rule is a historical guideline tested over about 30 years, not a guarantee for any specific future or a longer horizon. Treat the output as a planning estimate, not personalized financial advice; for decisions that affect your retirement, consult a qualified advisor.
Frequently asked questions
What is the 4% rule, and where does 25× come from?
The 4% rule says you can withdraw 4% of your starting portfolio in year one, then adjust that amount for inflation each year, and the money should last roughly 30 years. Dividing annual expenses by 0.04 is the same as multiplying them by 25, which is why a 4% rate produces a target of 25 times your spending.
Should early retirees use a lower withdrawal rate?
Often yes. The 4% rule was tested over about 30 years. If you plan to draw on the portfolio for 40 or 50 years, a lower rate such as 3.0% to 3.5% leaves more margin for bad market sequences. A 3.5% rate raises the target to roughly 28.6 times expenses.
Why does the calculator ask for a real return instead of a nominal one?
Real return is the nominal return minus inflation. Using it keeps every figure in today's dollars, so the target and the projection share the same purchasing power. If you expect 7% nominal growth and 3% inflation, enter 4% as the real return.
What happens if my numbers never reach the target?
If the balance is not growing toward the goal (for example, a 0% real return with no contributions and savings below the target), the projection reports that the target is unreachable rather than running forever. Raising contributions or the real return will produce a finite number of years.
Does the calculator account for Social Security or a pension?
No. It sizes a portfolio to cover your full annual expenses on its own. If you expect guaranteed income, subtract that from your annual expenses before entering them, and the target will shrink accordingly.