Free FIRE calculator · portfoliomath.app
FIRE calculator for the year you can quit.
A live financial independence (FIRE) calculator that turns savings rate and spending into a retirement year — plus a what-if stock calculator, averaging down, the true cost of a car, and a freelance hourly rate. Drag a slider. Watch the math reprice your life. No signup.
Live FIRE playground
2045
At a 42% savings rate and $48,000 of spending, the 4% rule says you are done in 18 yr. Target nest egg: $1,200,000.
Years to FI vs savings rate
7% real · 4% SWR
The classic curve: every extra point of savings rate buys disproportionately more years of freedom, because you save more and need less.
Free wealth calculators
Every tool is interactive. Change an input and the result updates immediately — built for time-on-page, not form submissions.
01
FIRE calculator
Turn income, spending, and savings rate into a financial independence date. Built on the 4% rule, with Coast, Lean, and Fat FIRE numbers.
02
What if I'd invested
Enter how much you put into specific stocks in a year and see what that money would be worth today, with a live price path.
03
Average-down calculator
See your new average entry price after buying the dip in crypto or stocks, plus break-even bounce and mark-to-market P/L.
04
True cost of a car calculator
The loan payment is not the cost. Add insurance, gas, maintenance, registration, and depreciation for a realistic monthly number.
05
Freelance hourly rate calculator
Price your time from desired salary, business expenses, time off, and billable hours so you stop undercharging.
Years to FIRE by savings rate
Starting from $0 invested, 7% real (after-inflation) returns, and a 4% safe withdrawal rate. This is the same curve as the playground above — a higher savings rate both invests more and lowers the FIRE number you have to hit.
| Savings rate | Years to FI | What it means |
|---|---|---|
| 10% | 42 yr | Typical 401(k) path — FI near a traditional retirement age |
| 15% | 35 yr | Typical 401(k) path — FI near a traditional retirement age |
| 20% | 31 yr | Aggressive saver — FI in a working lifetime |
| 25% | 27 yr | Aggressive saver — FI in a working lifetime |
| 30% | 24 yr | Aggressive saver — FI in a working lifetime |
| 40% | 19 yr | Classic FIRE pace — independence in the 30s or 40s for many |
| 50% | 15 yr | Classic FIRE pace — independence in the 30s or 40s for many |
| 60% | 11 yr | Lean / high-income FIRE — often under a decade |
| 70% | 8.3 yr | Lean / high-income FIRE — often under a decade |
How the FIRE calculator works
FIRE number
Annual expenses divided by your safe withdrawal rate. At 4%, you need 25× spending invested. At 3.5%, about 29×. The full FIRE calculator lets you set the rate, current portfolio, and expected return.
Savings rate
(Income − spending) ÷ income. It is the sharpest lever in financial independence math because it compounds twice: more dollars invested each year, and a smaller nest egg required.
The 4% rule
From William Bengen and the Trinity Study: withdrawing 4% in year one, then adjusting for inflation, historically lasted 30 years in a diversified portfolio. Early retirees often stress-test 3–3.5%.
Results are educational illustrations, not a plan, forecast, or recommendation. Sequence-of-returns risk, taxes, and healthcare can move the date. Use the sliders to see sensitivity, then add a margin.
FIRE calculator FAQ
- What is a FIRE calculator?
- A FIRE calculator estimates when you can reach financial independence and retire early. It uses your income, spending, current investments, expected returns, and a safe withdrawal rate to project the year your portfolio can cover your expenses.
- How do you calculate a FIRE number?
- FIRE number = annual spending ÷ safe withdrawal rate. At the classic 4% rule, that is 25× your annual expenses. Spending $48,000 a year means a $1.2 million target. A 3.5% rate (common for longer early-retirement horizons) is about 28.6× spending.
- How long does it take to reach FIRE?
- Savings rate is the main lever. From a $0 portfolio, 7% real returns, and a 4% withdrawal rate, a 25% savings rate takes roughly 32 years, 50% about 17 years, and 70% under 9 years. Raising savings both adds more each year and shrinks the pile you must build.
- Is the 4% rule still valid?
- The 4% rule comes from Bengen (1994) and the Trinity Study (1998) for 30-year retirements. Early retirees planning 40–50 years often model 3–3.5% instead. portfolioMath lets you set the withdrawal rate rather than locking 4%.
- Can I see what a past stock purchase would be worth now?
- Yes. The what-if calculator lets you enter dollar amounts for specific tickers in a given year and shows the value today using split-adjusted monthly prices. You can invest once, spread the amount across that year, or repeat it every year since.
- Are these calculators free?
- Yes. The FIRE, what-if stock, average-down, car cost, and freelance rate calculators on portfoliomath.app are free to use, with no account required.
- Is portfolioMath financial advice?
- No. The tools are educational illustrations of standard formulas. Taxes, sequence-of-returns risk, healthcare, and changing spending are not fully modeled. Use them to feel the math, then plan with a professional if you need advice.