Calculate-Compare-Decide
Find the amount you need invested today so compound growth alone carries you to retirement — with zero further contributions. See how close you are, when you'd hit it, and what happens when markets don't cooperate.
Social security reduces the portfolio you need. Volatility drives the Monte Carlo spread — 15% is roughly the historical S&P 500 figure.
The same plan under conservative, expected and optimistic real returns — because the return you assume changes everything.
Real markets don't deliver a steady return. This runs 1,000 randomised market paths to your retirement age.
A Coast FIRE calculator estimates the amount you need invested today so that compound growth alone will carry your portfolio to your full retirement number by your target age — with no further retirement contributions. It works backwards from your FIRE number using your expected real return and years to retirement.
Coast FIRE is the point where you have enough invested that compounding alone reaches your retirement goal on time, so you can stop saving for retirement. You still work to cover today's expenses, but the retirement problem is solved. It arrives years — often decades — before full financial independence.
Worked example — a 30-year-old retiring at 65. They want $40,000 a year. At a 4% withdrawal rate, the FIRE number is 40,000 ÷ 0.04 = $1,000,000. With 35 years to go and a 7% real return, the Coast FIRE number is 1,000,000 ÷ 1.07³⁵ = $93,663. Invest that once and never add another dollar, and it compounds to $1M by 65.
The part nobody tells you: the target moves. Your Coast FIRE number rises every year, because there's less time left to compound. That same $1M goal needs $93,663 at 30, $184,249 at 40, and $362,446 at 50. You are chasing a target that runs away from you at exactly your rate of return — which is why, with zero contributions, someone below the line never catches up. Contributions are the only thing that closes the gap.
Use real returns, not nominal. If you assume 10% nominal with 3% inflation, your real return is (1.10 ÷ 1.03) − 1 = 6.8%, not 7%. Every figure on this page is in today's dollars, so the spending target you enter is the spending power you actually get.
| Your age | Years to compound | Coast FIRE number | What it means |
|---|---|---|---|
| 25 | 40 | $66,780 | Start here and the rest is time |
| 30 | 35 | $93,663 | The classic milestone |
| 35 | 30 | $131,367 | Still very achievable |
| 40 | 25 | $184,249 | Nearly 2× the 30-year-old figure |
| 45 | 20 | $258,419 | The cost of waiting compounds too |
| 50 | 15 | $362,446 | Almost 4× the age-30 number |
| 55 | 10 | $508,349 | Half the goal, in cash, today |
| SWR | Multiple | On $40k/yr |
|---|---|---|
| 3.0% | 33.3× | $1,333,333 |
| 3.5% | 28.6× | $1,142,857 |
| 4.0% | 25× | $1,000,000 |
| 5.0% | 20× | $800,000 |
| Type | What it means |
|---|---|
| Coast FIRE | Stop saving; keep working |
| Barista FIRE | Part-time work covers the gap |
| Lean FIRE | Full FI on a frugal budget |
| Regular FIRE | 25× your spending; stop working |
| Fat FIRE | Full FI with no compromises |
| Real return | Coast FIRE number at 30 | Character |
|---|---|---|
| 4% (conservative) | $253,415 | Bonds-heavy, or a pessimistic equity view |
| 5% | $181,290 | Cautious |
| 7% (expected) | $93,663 | Roughly the long-run equity average |
| 9% (optimistic) | $47,570 | Bull-market assumption — don't plan on it |
A 4% vs 9% assumption changes the answer by more than 5×. This is the single biggest lever in any FIRE projection — and the one most calculators quietly hide.
Coast number $66,780 — reach it and compounding does the other 40 years.
Coast number $93,663. With $50k invested + $1k/mo, you coast in ~2.7 years.
FIRE $1.5M → coast number $276,374. Later start, bigger number.
FIRE $1.25M in only 15 years → coast number $453,058.
FIRE $3M. At 35, retiring at 65, coast number $394,101.
FIRE $625k. At 30, coast number is just $58,539.
Age 30, $1M goal → coast number jumps to $253,415.
Below the line with nothing invested monthly, you never coast — the target grows at your return rate.
Coast FIRE is the moment your retirement is already funded — you just haven't collected it yet. You have enough invested that compound growth alone will carry it to your full retirement number by your target age, so you can stop contributing to retirement entirely. You still work, and your salary still covers your rent and groceries, but the long-term problem is solved. Every dollar you earn from that point is for today.
The psychological shift is the point. You're no longer trapped by a job you hate because you need the 401(k) match. You can take the lower-paid role you'd enjoy, drop to four days, start the business, or take a year off — because the retirement machine keeps running without you feeding it.
Two steps. First, find your FIRE number: annual retirement spending ÷ your safe withdrawal rate. At 4%, that's 25× your spending. Second, discount it back to today using your expected real return. If you need $1M in 35 years and expect a 7% real return, you need $93,663 today — because $93,663 × 1.07³⁵ = $1,000,000.
Your Coast FIRE number is not a fixed finish line. It rises every single year, because each year that passes is one less year of compounding. At 30 you need about $93,700; at 40, $184,200; at 50, $362,400 — nearly four times the figure, for exactly the same retirement.
This has a brutal corollary that follows directly from the math: if you're below your Coast number and you contribute nothing, you will never reach it. Your portfolio grows at your return rate — but so does the target. The gap never closes. Contributions are the only mechanism that gets you across the line. The calculator above will tell you this honestly rather than showing a comforting curve.
Regular FIRE means you can stop working entirely — 25× spending in the bank. Lean FIRE is the same on a deliberately frugal budget. Fat FIRE is the same with no compromises. Barista FIRE sits between Coast and full FIRE: part-time work covers your current expenses (often for the health insurance), while investments keep compounding untouched. Coast FIRE is the earliest and most achievable of them all, which is exactly why it's the most useful milestone for most people.
The 4% rule comes from the Trinity Study: withdraw 4% of your portfolio in year one, adjust for inflation each year after, and historically the money lasted 30 years in the overwhelming majority of periods. It gives the tidy 25× multiple.
But it deserves scepticism. It was based on US historical data over a 30-year retirement — and an early retiree might need 50 or 60 years. Many in the FIRE community now use 3.25% to 3.5%, which raises the multiple to roughly 29–31×. Dropping from 4% to 3% raises a $1M FIRE number to $1.33M. The calculator lets you test all of them, because this assumption deserves your attention rather than your trust.
Everything hinges on the return you assume, and it's where optimism does the most damage. The US market's long-run real return has been around 7%, but that's an average across a century that included decades of stagnation. A 4% assumption puts your age-30 coast number at $253,415; a 9% assumption puts it at $47,570 — a 5× difference from the same goal.
Always work in real (inflation-adjusted) terms, as this page does. And subtract your fees: a 1% expense ratio doesn't sound like much, but across 35 years it can consume a fifth of your final balance. Index funds at 0.03–0.10% exist precisely to avoid that.
A constant 7% return is a fiction. Markets deliver +25% one year and −18% the next, and the order matters — a crash early in retirement while you're withdrawing does far more damage than the same crash later, even with identical average returns. That's sequence of returns risk, and it's why the Monte Carlo simulation on this page exists: it runs a thousand randomised paths so you can see the range of outcomes rather than a single flattering line.
Assuming 10% real returns instead of 7%. Forgetting inflation entirely. Counting home equity or an emergency fund as invested assets. Using 4% for a 50-year retirement. Ignoring fees. Reaching Coast FIRE and then actually stopping all saving — remember it only guarantees your retirement, not a house deposit, your kids' education, or a health emergency. And the quiet one: treating a single projection as a prediction. It's a scenario, not a promise.
Reaching Coast FIRE doesn't mean stopping. Most people keep investing and simply pull their retirement date forward — every extra dollar now buys freedom sooner. Others redirect the money to life today: shorter hours, a career change, travel, time with children who are small only once. The point of Coast FIRE isn't the number. It's that the number gives you the option.
Coast FIRE is the point where you have enough invested that compound growth alone will carry your portfolio to your full retirement number by your target age, without any further retirement contributions. You still work to cover your living costs, but you no longer need to save for retirement. It is a milestone on the way to full financial independence.
First find your FIRE number by dividing your annual retirement spending by your safe withdrawal rate, such as 4 percent, which gives 25 times spending. Then discount that back to today by dividing it by one plus your real return, raised to the number of years until retirement. The result is the amount you need invested now.
A 30 year old who wants to retire at 65 on 40,000 dollars a year needs a FIRE number of 1,000,000 dollars at a 4 percent withdrawal rate. Assuming a 7 percent real return over 35 years, the Coast FIRE number today is about 93,700 dollars. Once invested, that alone grows to a million by 65.
Yes, and this is what most people miss. The Coast FIRE number rises every year because there is less time left for compounding. At 30 you might need 93,700 dollars, but at 40 the same goal needs about 184,000 and at 50 about 362,000. The target moves away from you, which is why starting early matters so much.
Regular FIRE means having enough invested to stop working entirely and live off withdrawals. Coast FIRE is an earlier milestone: you have enough that you no longer need to save for retirement, but you still work to cover your current expenses. Coast FIRE arrives many years before full FIRE and offers immediate freedom in career choices.
The 4 percent rule is a guideline suggesting you can withdraw about 4 percent of your portfolio in the first year of retirement, adjusting for inflation thereafter, with a strong likelihood the money lasts 30 years. It comes from the Trinity Study. It implies a FIRE number of 25 times your annual spending, though many now prefer a more conservative 3 to 3.5 percent.
Barista FIRE is when you have enough invested to cover most of your retirement needs but still work part time, often for health insurance or to cover a portion of expenses without drawing down the portfolio. It sits between Coast FIRE and full FIRE, letting investments continue to grow while part time income covers current living costs.
No. It is an educational estimation tool. Projections assume a constant real return, which real markets never deliver. Actual results depend on market returns, sequence of returns risk, taxes, fees, inflation and your own behaviour. Use it to explore scenarios, not to make decisions alone, and consult a qualified financial professional.
No, not if you are currently below your Coast FIRE number. Your portfolio grows at your return rate, but so does the Coast FIRE target, because each passing year removes a year of compounding. The gap therefore never closes on its own. Contributions are the only thing that moves you across the line.
Most people use a real, inflation-adjusted return of about 7 percent, roughly the long run average for US equities. Being more conservative at 5 percent is prudent, especially near retirement. Avoid optimistic assumptions above 8 percent real: at 9 percent the required number is barely a fifth of the 4 percent figure, which flatters the plan dangerously.
Use real returns, meaning after inflation, and keep every figure in today's money. If you expect 10 percent nominal with 3 percent inflation, your real return is about 6.8 percent, not 7. Working in real terms means the spending target you enter is the actual purchasing power you will get, which is what matters.
Generally no. Coast FIRE counts invested assets that compound and can be withdrawn from, such as retirement accounts and brokerage investments. Your home does not produce retirement income unless you sell or downsize, and you still need somewhere to live. Similarly, exclude your emergency fund, since it is not invested for growth.
A crash can push you back below your Coast FIRE number, and you may need to resume contributions. This is why a single projection is misleading. The Monte Carlo simulation on this page runs a thousand randomised market paths so you can see the realistic range of outcomes rather than one smooth, flattering curve.
You can, but you do not have to, and many people do not. Coast FIRE only guarantees your retirement, not a house deposit, education costs or a health emergency. Most people who reach it keep investing and simply retire earlier, or redirect the money toward working less. The value is the option, not the obligation.
Yes. The share button copies a link that encodes your age, portfolio, contributions and assumptions, so you can revisit the projection or send it to a partner or planner. You can also print or save a roadmap as a PDF. Everything runs in your browser and nothing is uploaded or stored on a server.