Free FI calculator — no signup
Find your FI number
Enter four numbers and instantly see the portfolio that funds your life, roughly when you could reach financial independence, and whether you've already hit Coast FIRE. Estimates you can edit — no hidden assumptions.
What you'll spend per year once work is optional — today's dollars, not your current income.
Investments and savings earmarked for FI. Exclude home equity.
Amount added to investments per year.
Everything is computed in your browser. Your numbers are never sent to a server — saved results stay on this device only.
Your FI number
$1,000,000
$40,000/yr of spending ÷ 4% withdrawal rate (25× your annual spending) — in today's dollars.
Free, no card — your numbers ride along privately to pre-fill it.
Years to FI
~23 years — around 2050, at age 58.
Coast FIRE
Coast FIRE number at age 65 is $231,377 — you're 22% of the way there.
Coast FIRE means your current investments alone, with no further contributions, would grow to your FI number by your target age.
Projected balance
Saving $20,000/yr on top of $50,000 invested, you're on track to reach financial independence in about 23 years — an estimate, in today's dollars.
Estimates, not financial advice. Assumptions are shown and editable. All values in today's dollars.
Turn this into a real plan — free, no card
This is a simplified estimate. Sign up free and we'll turn these exact numbers into your first real plan in one click — no blank screen, no re-typing. Your real plan adds taxes, one-off milestones, and a Monte Carlo chance-of-success — and it stays alive as your money moves. Free, no card.
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How this works
FI number. Your FI number is your annual spending divided by a safe withdrawal rate (SWR). The 4% default — equal to 25 times annual spending — comes from William Bengen's 1994 research and the Trinity study, which tested withdrawal rates against historical markets over roughly 30-year retirements. For a 40–50 year early-retirement horizon, many planners use a more conservative 3.25–3.5%; the calculator has a one-tap 3.5% preset.
Years to FI. We compound your current invested total plus your yearly contributions at your expected real (after-inflation) return until the balance reaches your FI number. Working in real terms keeps everything in today's dollars — the default of 5% real is roughly 7% nominal growth minus 2% inflation, and both figures are shown and editable in the assumptions.
Coast FIRE. Your Coast FIRE number is your FI number discounted back by your expected real return over the years until your target retirement age — the amount that would get there on growth alone, with no further contributions.
This is deliberately a simplified model: no taxes, no one-off events, and a single constant return instead of a range of market outcomes. That's the gap a full plan fills.
Want the full story behind the math — formula, worked examples, and the 4%-rule fine print? Read What is your FI number?
Sources: Bengen, W. P. (1994), "Determining Withdrawal Rates Using Historical Data," Journal of Financial Planning; Cooley, Hubbard, and Walz (1998), the "Trinity study."
FIManager provides financial planning tools and projections for educational purposes. Projections are estimates based on assumptions you set and are not guarantees or personalized investment, tax, or legal advice.
FI number by annual spending
The same arithmetic at the two most common withdrawal rates — spending ÷ SWR, in today's dollars.
| Annual spending | FI number at 4% SWR (25×) | FI number at 3.5% SWR (~28.6×) |
|---|---|---|
| $30,000 | $750,000 | $857,143 |
| $40,000 | $1,000,000 | $1,142,857 |
| $50,000 | $1,250,000 | $1,428,571 |
| $60,000 | $1,500,000 | $1,714,286 |
| $80,000 | $2,000,000 | $2,285,714 |
| $100,000 | $2,500,000 | $2,857,143 |
Frequently asked questions
- What is an FI number?
- Your FI number is the portfolio size that can fund your annual spending indefinitely — annual spending divided by a safe withdrawal rate. At the widely used 4% rate that works out to 25 times your annual spending, so $40,000 a year of spending means a $1,000,000 FI number. It's an estimate that moves with your spending and assumptions, not a guarantee.
- How is the FI number calculated?
- FI number = annual spending ÷ safe withdrawal rate (SWR). The 4% SWR comes from Bengen's 1994 research and the Trinity study, which tested withdrawal rates over roughly 30-year retirements. Years to FI then follows from compounding your current investments plus yearly contributions at your expected real (after-inflation) return until they reach that number.
- Is the 4% rule safe for early retirement?
- The 4% rule was tested against roughly 30-year retirements, so a 40–50 year early-retirement horizon carries more risk of outliving the money. Many planners use 3.25–3.5% for long horizons, which raises the target to about 29–31 times annual spending — this calculator includes a one-tap 3.5% preset. Treat any withdrawal rate as an assumption to stress-test, not a promise.
- What is Coast FIRE?
- Coast FIRE means you've already invested enough that growth alone — with no further contributions — would reach your FI number by your target retirement age. The Coast FIRE number is your FI number discounted back by your expected real return over the years until that age. Hitting it means you could cover just your living costs from here and still be on track to retire on schedule.
- Does this calculator store or send my financial information?
- No. All of the math runs in your browser and your financial inputs are never sent to a server. If you return later, your last inputs are restored from storage on your own device only, and the optional email signup sends just your email address — none of your numbers.
- Are these projections guaranteed?
- No — they're estimates in today's dollars, based on assumptions you can see and edit: expected real return, withdrawal rate, and target age. Real markets don't return the same amount every year, and this simplified calculator ignores taxes and one-off events. A fuller plan should model those, plus a range of outcomes rather than a single line.
Explore the FIRE variants
Same core math, different target spend and gap-covering plan. See the number for the flavor of FIRE you're aiming at.
- What is your FI number? The formula, the 4% rule, and worked examples behind every number here.
- Coast FIRE calculator The smaller amount that grows to full FI on its own — stop saving, keep coasting.
- Barista FIRE calculator How steady part-time income shrinks the portfolio you need to semi-retire.
- Lean FIRE calculator Reach financial independence sooner on a deliberately frugal budget.
- Fat FIRE calculator Fund a no-compromises, higher-spending early retirement.
- Chubby FIRE calculator The comfortable middle band between lean and fat FIRE.