FIRE Calculator
FIRE — Financial Independence, Retire Early — is reached when your investments can cover your spending. Your FIRE number is annual expenses ÷ safe withdrawal rate (about 25× expenses at 4%). This calculator finds that number and how many years of saving it takes to get there.
Use this FIRE calculator to see your target and your timeline. Enter your expected annual expenses and withdrawal rate to get your FIRE number, then your current savings, yearly contributions and expected return to find how many years until your portfolio can support you.
Enter your spending and savings, then press Calculate.
How the FIRE calculator works
FIRE turns on a single number. Divide your expected annual expenses by your safe withdrawal rate, and you get the portfolio size that can fund your life indefinitely — the FIRE number. At the classic 4% rate that is 25 times your yearly spending, but you can dial the rate up or down and watch the target move. Lower spending or a higher withdrawal rate both shrink the number you have to reach.
The second half is timing. The calculator grows your current savings and each year's contributions at your expected return until the total hits your FIRE number, and reports the years. Your savings rate is the master lever — it fills the portfolio faster and lowers the spending it must cover. Explore the trajectory with the investment growth calculator and see raw compounding in the compound interest calculator.
The FIRE formulas
- 4% rule — a 25× multiple of expenses
- Savings rate — the biggest lever on the timeline
- Return — use a real (after-inflation) rate for a real timeline
Your savings rate is everything
The counter-intuitive truth of FIRE is that how much you save matters far more than how much you earn or even how the market performs. A high savings rate works twice: it pours money into the portfolio faster, and it means you live on less, which lowers the FIRE number itself. Someone saving half their income needs a smaller nest egg and fills it quicker than someone saving a tenth, so their timeline can be measured in years rather than decades. Cutting recurring expenses is the single most powerful move you can make.
Treat the number as a plan, not a promise
The 4% rule rests on history, and early retirement stretches it — your money may need to last forty or fifty years, not thirty. A rough patch of returns in the first few years is the biggest threat, so many aiming for FIRE use a more cautious 3% to 3.5% rate, keep a cash cushion, or stay willing to earn a little or trim spending if markets sour. Use this calculator to set a clear target and timeline, then build in flexibility rather than betting everything on a single withdrawal rate.
Barista, Coast, Lean and Fat FIRE explained
FIRE is not one-size-fits-all, and the variations change your target number. Lean FIRE means reaching independence on a frugal budget, so a smaller nest egg; Fat FIRE aims for a comfortable, higher-spending lifestyle and a bigger number. Coast FIRE means you have invested enough early that growth alone will fund a normal-age retirement, so you only need to cover today's living costs and can stop adding to retirement savings. Barista FIRE sits in between: you semi-retire and let a part-time job cover part of your spending — often taken for the benefits — while your portfolio keeps compounding. All four run on the same maths; they simply set a different target and timeline.
Estimate only — not investment advice. Returns are not guaranteed and the 4% rule is a guideline. Use a real (after-inflation) return for a realistic timeline and plan a margin of safety.
How to use it & key terms
Enter your annual expenses and withdrawal rate, then your current savings, annual savings and expected return, and press Calculate to see your FIRE number and years to reach it.
| Term | What it means |
|---|---|
| FIRE | Financial Independence, Retire Early. |
| FIRE number | The portfolio that can fund your spending indefinitely. |
| 4% rule | Withdraw ~4% a year; implies a 25× target. |
| Safe withdrawal rate | The yearly % you can take with low risk of running out. |
| Savings rate | The share of income you invest — the key lever. |
| Coast FIRE | Enough saved that growth alone funds a normal retirement. |
Sources & methodology
The FIRE number is the annual expenses divided by the safe withdrawal rate — equivalent to a 25-times multiple of expenses at the classic 4% rate. The years to financial independence are found by growing the current savings and annual contributions (added as a year-end annuity) at the expected annual return until the total reaches the FIRE number, solving for the time from the future-value-of-an-annuity relationship. For a realistic horizon, use an inflation-adjusted (real) return. The 4% rule derives from historical safe-withdrawal-rate studies and is a guideline rather than a guarantee.
Sources: The 4% safe-withdrawal-rate guideline and the 25x rule; standard future-value-of-an-annuity compounding. Returns illustrative.
The part the math doesn't show
The calculator above can tell you the size of the portfolio and the number of years, but it stays silent on the questions that decide whether early retirement actually feels like freedom. The first is simply: retire to what? People who leave work with a clear sense of how they want to spend their days — projects, people, travel, learning, volunteering — tend to thrive. Those who retire mainly to escape a job they dislike can find that the empty calendar brings its own restlessness. A number without a purpose behind it is only half a plan.
A second, very human trap is the “one more year” loop. As the target draws near, the safety of a steady paycheck and the fear of leaving too soon can make the finish line keep sliding forward. There is nothing wrong with padding the numbers, but it helps to decide in advance what “enough” looks like, so the goalposts stop moving on their own. Endlessly deferring the life you were saving for defeats the point of saving for it.
Flexibility is the quiet secret of durable early retirement. The people who make it work are rarely the ones who nailed a single withdrawal rate; they are the ones who stay adaptable — willing to trim spending in a rough year, pick up occasional paid work they enjoy, or lean on a cash cushion so they are never forced to sell investments at the worst possible moment. A plan with a little slack in it survives surprises that a rigid one cannot.
There are practical wrinkles the headline figure hides, too. Retiring years before the traditional retirement age means bridging a gap: covering health coverage that an employer once provided, and arranging access to money before the ages at which retirement accounts normally unlock. These are solvable, but they take deliberate planning rather than an afterthought once you have already handed in your notice. Treat the FIRE number as a compass heading rather than a destination, revisit it as your life and the markets change, and give as much thought to the years after the number as you gave to reaching it.
Frequently asked questions
What is FIRE?
FIRE stands for Financial Independence, Retire Early. It is a movement built on saving and investing a large share of your income so that your investments can eventually cover your living expenses, freeing you from needing a paycheck. Once your portfolio is large enough that a safe withdrawal rate covers your annual spending, you are financially independent and can choose whether to keep working. The core idea is to reach that point far earlier than a traditional retirement age.
What is the 4% rule?
The 4% rule is a guideline suggesting you can withdraw about 4% of your portfolio in the first year of retirement, then adjust that amount for inflation each year, with a strong chance the money lasts 30 years or more. It comes from historical market studies. The flip side is the 25x rule: since 4% is one twenty-fifth, your target portfolio is roughly 25 times your annual expenses. This calculator lets you set your own withdrawal rate.
How is my FIRE number calculated?
Your FIRE number is your annual expenses divided by your safe withdrawal rate. At the classic 4% rate, that is 25 times your yearly spending — so $40,000 of expenses implies a $1,000,000 target. A more cautious 3.5% rate raises the multiple to about 29 times, while a more aggressive 5% lowers it to 20 times. Lower spending and a higher withdrawal rate both shrink the number you need to hit.
How long will it take me to reach FIRE?
That depends on how much you have saved, how much you add each year, and your investment return. The calculator grows your current savings and yearly contributions at your expected return until they reach your FIRE number, and reports the years. Your savings rate is the biggest lever: the more of your income you invest, the faster you both build the portfolio and lower the expenses it needs to cover, which is why high savers reach FIRE remarkably quickly.
Is the 4% rule safe?
The 4% rule held up well across most historical periods, but it is a guideline, not a guarantee. It can be strained by a poor sequence of returns early in retirement, higher inflation, or a very long retirement — all more relevant for early retirees whose money must last decades longer. Many in the FIRE community use a more conservative 3% to 3.5% rate, keep a cash buffer, or stay flexible with spending. Treat the number as a target to plan around, not a promise.
What are lean, fat and coast FIRE?
They are flavours of FIRE. Lean FIRE means reaching independence on a modest, frugal budget, so a smaller number. Fat FIRE means retiring with a comfortable, higher-spending lifestyle, so a larger number. Coast FIRE means saving enough early that, even with no further contributions, growth alone will fund a normal-age retirement — after which you only need to cover current expenses. Each is the same maths with a different target and timeline.
What is Barista FIRE?
Barista FIRE is a halfway version of financial independence where you stop full-time career work but keep a part-time or lower-stress job that covers some of your expenses, so your portfolio does not have to cover everything yet. The name comes from the idea of a coffee-shop job taken partly for the health benefits. It lets you step back sooner, ease the pressure on your savings, and let your investments keep growing until you reach full FIRE. It is popular with people who want more freedom now without waiting to hit their full number.
Is the 4% rule still safe?
The 4% rule, based on the Trinity study, is a useful starting guideline rather than a guarantee. It suggested that withdrawing 4% of your portfolio in year one, then adjusting for inflation, rarely ran out over a 30-year retirement. Critics point out that early retirees face much longer horizons, and that lower expected returns and a bad run of early losses, known as sequence-of-returns risk, can strain it, so many now favour a more cautious 3% to 3.5% or a flexible withdrawal that adjusts to the markets. Treat 4% as a benchmark and build in a margin of safety.
How long will my money last in retirement?
It depends on how much you have saved, how much you spend each year, and what your investments earn. A common starting point is the 4% rule: if you withdraw about 4% of your portfolio in the first year and adjust for inflation after that, history suggests the money has a good chance of lasting around 30 years. Spend a smaller share, say 3% to 3.5%, and it can last longer or even indefinitely, while spending more raises the risk of running short, especially if markets fall early on. For a long early retirement, lean toward a lower withdrawal rate and keep a cash cushion.