FIRE Calculator
Financial Independence, Retire Early comes down to one number: the portfolio size that covers your annual expenses indefinitely. Enter your income, expenses, savings, and current portfolio to see that number, a timeline, a Coast FIRE figure, and your savings rate, all based on the 4% safe withdrawal rate.
Updated
Educational purposes only.
This calculator provides estimates based on simplified assumptions. Actual results depend on market returns, inflation, taxes, healthcare costs, and other factors. The 4% rule is a guideline, not a guarantee. This is not financial advice.
Educational purposes only. These calculators illustrate concepts and do not constitute investment advice. Read our disclaimer
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<a href="https://www.stockcram.com/tools/calculators/fire-calculator" target="_blank" rel="noopener">FIRE Calculator</a>
by <a href="https://www.stockcram.com" target="_blank" rel="noopener">StockCram</a>
</p>What is FIRE?
FIRE stands for Financial Independence, Retire Early. The arithmetic centers on one number: the portfolio size at which a chosen withdrawal rate covers annual expenses. Reaching it depends far more on the share of income saved than on the size of that income.
The formula
FIRE number = annual expenses ÷ withdrawal rate- annual expenses = spending the portfolio must cover
- withdrawal rate = the fraction taken out each year, e.g. 0.04
Annual expenses of $50,000 at a 4% withdrawal rate give 50,000 ÷ 0.04 = $1,250,000. The same arithmetic is often expressed as the Rule of 25, meaning 25 × annual expenses, because dividing by 4% and multiplying by 25 are the same operation. At a 3.5% rate the target rises to about $1,428,600; at 5% it falls to $1,000,000.
The savings rate matters more than the salary
Saving a larger share of income does two things at once: it adds more to the portfolio each year, and it lowers the annual expenses the portfolio eventually has to cover. Because the target is a multiple of spending, cutting spending pulls the finish line closer while simultaneously running faster toward it.
That double effect is what makes the standard FIRE tables depend on the savings rate rather than the salary. Two people saving the same percentage arrive in the same number of years regardless of what they earn, assuming the same return.
| Savings rate | Approximate years |
|---|---|
| 10% | about 51 |
| 25% | about 32 |
| 50% | about 17 |
| 65% | about 10.5 |
| 75% | about 7 |
Standard FIRE arithmetic assuming a constant return and constant spending. Real returns vary year to year, and past performance does not indicate future results.
Where the 4% figure comes from, and what it leaves out
The 4% figure comes from William Bengen's paper "Determining Withdrawal Rates Using Historical Data" (Journal of Financial Planning, October 1994) and the 1998 Trinity Study that followed it. Both examined historical US stock and bond returns and asked what withdrawal rate would have survived a 30-year retirement across past periods. Rates near 4%, adjusted annually for inflation, survived most of the historical windows tested.
Two limits are worth stating plainly. The study modeled 30 years, and an early retirement may need to fund fifty or more. And it is a backward-looking measure of what would have worked historically, not a guarantee about future periods. Later research has argued for both lower and higher figures depending on portfolio mix, fees and flexibility of spending.
Underneath most of that argument sits the order of returns, not their average. Two portfolios can post identical average returns and end up in very different places if those returns arrive in a different sequence. Poor returns early in retirement do disproportionate damage, because withdrawals are coming out of a shrinking balance and fewer shares are left to recover when markets rise.
That is the main reason a single average-return projection understates the range of outcomes. The same average, reordered, can leave a portfolio in a substantially different position after a decade, and no single withdrawal rate can be right for every sequence.
Lean, fat and coast
The same arithmetic picks up different labels depending on the spending assumption, and one of the three is not really the same calculation at all.
- Lean FIRE uses a deliberately low expense figure, producing a smaller target.
- Fat FIRE assumes higher spending and a correspondingly larger target.
- Coast FIRE marks the point at which the existing balance, left to compound with no further contributions, would reach the target by a chosen retirement age. It answers when contributions could stop rather than when work could.
What this calculator does not account for
- The return rate is constant. Real sequences vary, and the order matters as much as the average.
- Spending is treated as flat in real terms, with no allowance for healthcare changes, one-off costs or spending that falls later in retirement.
- Taxes on withdrawals are not modeled, and they differ sharply between taxable, traditional and Roth accounts.
- The withdrawal rate is applied mechanically, with no adjustment in response to market conditions.
- Social Security, pensions and any other later income sources are excluded.
Both land on a target balance, but they start from opposite ends. FIRE arithmetic begins with a multiple of spending at any age, while the retirement calculator begins with a conventional retirement age and a replacement income. Retirement Calculator
How It Works
Enter your current situation
Your age, income, annual expenses, savings amount, and current portfolio value.
Set your assumptions
Expected annual return and safe withdrawal rate (default 4%, the widely cited guideline).
See your FIRE number
The portfolio value needed to cover your expenses indefinitely.
Review your timeline
See your FIRE age, years to FIRE, Coast FIRE number, savings rate, and full projection.
Frequently Asked Questions
FIRE stands for Financial Independence, Retire Early. It is a movement and financial strategy focused on aggressive saving and investing to build enough wealth to cover living expenses indefinitely, allowing you to become financially independent and potentially retire much earlier than the traditional age of 65.
Your FIRE number is the total portfolio value you need to sustain your lifestyle indefinitely. It is typically calculated as your annual expenses multiplied by 25 (based on the 4% safe withdrawal rate). For example, if you spend $40,000 per year, your FIRE number is $1,000,000. Some use a multiplier of 30 or 33 for a more conservative approach.
The 4% rule (also called the safe withdrawal rate) is a guideline from the Trinity Study suggesting you can withdraw 4% of your portfolio in the first year of retirement, then adjust for inflation each year, and your money has a high probability of lasting 30+ years. It is a starting point, not a guarantee — actual results depend on market conditions.
Coast FIRE means you have enough saved that, even without additional contributions, your portfolio will grow to your full FIRE number by your target retirement age through investment returns alone. Once you reach Coast FIRE, you only need to earn enough to cover current expenses. Your future retirement is already funded by existing investments.
The standard FIRE arithmetic gives roughly 17 years at a 50% savings rate, about 32 years at 25%, and under 10 years at 75%, assuming a constant return. Savings rate, not income, is what drives the timeline.
Common FIRE variants include: Lean FIRE (minimal expenses, typically under $40K/year), Fat FIRE (maintaining a higher lifestyle, $100K+/year), Coast FIRE (enough saved to stop contributing), and Barista FIRE (semi-retired, working part-time for health insurance and small expenses). Each represents a different balance of saving, lifestyle, and work.
This calculator uses nominal returns (not inflation-adjusted). To approximate real returns, you can enter a lower expected return rate. For example, if you expect 7% nominal returns and 3% inflation, entering 4% gives you a rough inflation-adjusted projection. The FIRE number itself is based on current-year expenses.