Horizon changes safe withdrawal
A 40- or 50-year retirement faces greater sequence-of-returns risk than the classic 30-year Trinity study window.
FIRE Calculator
Estimate how much you need—and how long it could take—to reach financial independence with transparent assumptions.
Your FIRE plan
All projections are shown in today's purchasing power.
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Estimated time to financial independence23.1 yearsEstimated FIRE age: 53.1 years old
Your FIRE number$900,000
Current progress5.6%
Amount remaining$850,000
Real annual return4.9%
Annual portfolio funding gap$36,000
3% (33.3×)$1,200,000
3.5% (28.6×)$1,028,571
4% (25×)$900,000
Educational estimate only. Returns, inflation and sustainable withdrawal rates can change over time.
How the FIRE number is calculated
Your FIRE target is based on expected annual spending and the percentage withdrawn from the portfolio. At a 4% rate, the target equals roughly 25 times annual spending.
FIRE number = Annual spending / Safe withdrawal rate
Example: $40,000 of annual spending at a 4% withdrawal rate produces a $1,000,000 FIRE target in today’s money.
Real return matters more than nominal return
The calculator adjusts returns for inflation and projects the portfolio in today's purchasing power. This avoids comparing a target in today's money with a future nominal balance.
Real return = (1 + nominal return) / (1 + inflation) − 1
Frequently asked questions
What is a FIRE number?
A FIRE number is the estimated portfolio needed to fund annual spending at a chosen withdrawal rate. The basic formula is annual spending divided by the withdrawal rate.
Is the 4% rule guaranteed to be safe?
No. It is a planning starting point, not a guarantee. Retirement length, asset allocation, taxes and market conditions all affect sustainability.
Why does the calculator use returns after inflation?
The FIRE target and spending are expressed in today's purchasing power, so the portfolio is projected with a real return for a consistent comparison.
Stress-test your independence target
The 4% rule was designed as a historical floor for 30-year retirements, not a universal guarantee. Longer horizons, changing market valuations and healthcare costs require you to stress-test your FIRE target across multiple withdrawal scenarios.
Net gap is the real target
Subtract dependable non-portfolio income (pensions, real estate rent) before multiplying annual expenses.
Flexibility beats a higher number
Being able to trim discretionary spending by 10-15% during severe drawdowns protects portfolio longevity far more than saving an extra decade.
Tax drag belongs in expenses
Withdrawals from taxable and tax-deferred accounts generate liabilities that must be budgeted as living costs.
Step-by-step example
Worked example: annual spending vs target capital
Targeting $40,000 in annual spending with $10,000 in predictable rental income leaves a $30,000 portfolio gap.
- Rule of 25 (4% withdrawal rate): $30,000 × 25 = $750,000 target portfolio.
- Cautious 3.33% rate (30× gap): $30,000 × 30 = $900,000 target portfolio.
- Ultra-safe 3% rate (33.3× gap): $30,000 × 33.3 = $1,000,000 target portfolio.
- Choose a withdrawal band, not a single brittle target number.
Takeaway: Comparing multiple safe withdrawal rates shows the real tradeoff between years worked and portfolio resilience.
Annual net spending gap1.0×
4% target25× gap
3.33% target30× gap
3% target33.3× gap
What should you enter for a better result?
| Field | What to enter | Why it matters |
|---|---|---|
| Retirement spending | Build from housing, food, healthcare, tax, travel and irregular costs. | Directly scales the target. |
| Reliable income | Only include income you reasonably expect during retirement. | Reduces the portfolio funding gap. |
| Withdrawal rate | Compare several rates; longer horizons generally deserve more caution. | The denominator of your FIRE number. |
| Return and inflation | Stress-test lower returns and higher inflation together. | Controls the accumulation timeline. |
Cross-checked against major and official sources
These references were used to cross-check input design, formulas, model limits or current rules. Links open in a new tab so you can verify the methodology yourself.
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