The short answer
- Your FIRE number is your yearly spending divided by your withdrawal rate. At 4%, that is 25 times what you spend.
- Someone spending $50,000 a year needs $1,250,000 invested, in today’s dollars.
- The time it takes depends mainly on your savings rate. Saving 50% of take-home pay from scratch gets you there in about 17 years at a 7% return and 2.5% inflation.
- Early retirees face problems later retirees don’t: the 10% early withdrawal tax, health insurance before 65 and a retirement that may last 50 years.
What FIRE means
Financial independence means your investments can pay your living costs for the rest of your life, so work becomes a choice. Retiring early is what many people do with that freedom, but plenty keep working, switch to work they enjoy or go part-time. The movement grew online in the 2010s, but the maths behind it is the same maths that sits behind any retirement plan: how much you spend, how much you save and how fast your money grows.
What makes FIRE different is the timescale. A traditional plan saves 10% to 15% of pay for 40 years and leans on Social Security from the mid-60s. A FIRE plan saves 40%, 50% or more for 10 to 20 years, and has to bridge the decades before Social Security and Medicare begin.
Your FIRE number
The FIRE number is the size of portfolio that can pay your spending indefinitely, or at least for a very long retirement. It comes from a withdrawal rate: the share of the portfolio you take in the first year, then raise each year with inflation.
FIRE number = yearly spending ÷ withdrawal rate. At 4%, divide by 0.04, which is the same as multiplying by 25. At 3.5%, multiply by about 28.6. At 3%, multiply by about 33.3.
| Withdrawal rate | FIRE number | Years to FI |
|---|---|---|
| 3% | $1,666,667 | 25.3 |
| 3.25% | $1,538,462 | 24.1 |
| 3.5% | $1,428,571 | 22.8 |
| 4% | $1,250,000 | 20.8 |
| 4.5% | $1,111,111 | 19.1 |
| 5% | $1,000,000 | 17.7 |
The calculator works in today’s dollars, so the number stays the same however far away it is. It also shows the number in the dollars of the year you reach it, which is much bigger because prices rise in the meantime.
A worked example
- Saving a year ($80,000 − $50,000)$30,000
- Savings rate ($30,000 ÷ $80,000)37.5%
- FIRE number ($50,000 × 25)$1,250,000
- Real return (1.07 ÷ 1.025 − 1)4.39%
- Time to reach the number20.8 years
In the dollars of 2047 the target is about $2.09 million, because 2.5% inflation over nearly 21 years raises prices by about two-thirds. That is why the calculator thinks in today’s dollars: $1.25 million is the figure you can compare with your balance today.
Why the savings rate matters most
Your savings rate is the share of take-home pay you don’t spend. It drives FIRE in two ways at once. A higher rate means more money going in each year, and it also means lower spending, which means a smaller FIRE number. Pay rises only help if your spending doesn’t rise with them.
Because of this double effect, your income matters less than you might expect. Two people saving 50% of their pay reach FI in about the same time whether they take home $50,000 or $150,000, because each is building a portfolio sized to their own spending. The higher earner ends up with a bigger portfolio, but it takes them no longer to get there.
Years to FI by savings rate
| Savings rate | Spending a year | FIRE number | Years to FI |
|---|---|---|---|
| 10% | $72,000 | $1,800,000 | 55.2 |
| 15% | $68,000 | $1,700,000 | 45.7 |
| 20% | $64,000 | $1,600,000 | 38.9 |
| 25% | $60,000 | $1,500,000 | 33.6 |
| 30% | $56,000 | $1,400,000 | 29.3 |
| 40% | $48,000 | $1,200,000 | 22.4 |
| 50% | $40,000 | $1,000,000 | 17.1 |
| 60% | $32,000 | $800,000 | 12.7 |
| 70% | $24,000 | $600,000 | 8.8 |
The calculator draws this table for your own pay and your current savings. With $100,000 already invested, every row is shorter: 50% takes 14.7 years instead of 17.1, and 25% takes 29.1 instead of 33.6.
Spending cuts work twice
In the main example, each $5,000 of yearly spending moves the finish line by about three to four and a half years, because it changes both what you save and what you need.
| Spending a year | Savings rate | FIRE number | Years to FI |
|---|---|---|---|
| $45,000 | 43.8% | $1,125,000 | 17.6 |
| $50,000 | 37.5% | $1,250,000 | 20.8 |
| $55,000 | 31.3% | $1,375,000 | 24.6 |
| $60,000 | 25.0% | $1,500,000 | 29.1 |
The biggest wins usually come from the largest fixed costs: housing, cars and insurance. Use our rent affordability calculator or the auto loan calculator to test what a cheaper home or car would free up. A one-off cut to a recurring bill is worth more than a string of small daily sacrifices you won’t keep up.
The 4% rule and early retirement
The 4% rule comes from studies of US stock and bond returns published in the 1990s. Taking 4% of a balanced portfolio in the first year and raising the dollar amount with inflation each year after survived every 30-year period in the historical record. It is a rule of thumb drawn from the past, not a promise.
Early retirees need their money to last longer than 30 years. Someone stopping work at 45 might need 45 or 50 years of withdrawals. Over longer periods, the historical safe rate falls, which is why many early retirees plan on 3.25% to 3.5%. In the worked example, moving from 4% to 3.5% raises the FIRE number from $1,250,000 to $1,428,571 and adds two years of work.
Flexibility beats precision
The withdrawal rate assumes you never cut spending. In practice, being willing to spend a little less after a bad year makes a portfolio last far longer. A plan with some flexible spending can often use a higher starting rate than a rigid one.
Returns and inflation
The calculator turns your return and inflation into a real return: 7% with 2.5% inflation is a real return of 4.39%. Everything then grows at the real rate, so all the dollar figures are in today’s money.
| Return a year | Real return | Years to FI |
|---|---|---|
| 5% | 2.44% | 25.7 |
| 6% | 3.41% | 23.0 |
| 7% | 4.39% | 20.8 |
| 8% | 5.37% | 19.1 |
| 9% | 6.34% | 17.7 |
The return matters, but less than the savings rate, and you control it far less. Fund fees come straight off it: a 1% fee turns a 7% return into 6% and, here, adds more than two years. Low-cost index funds keep more of the return for you. Try a cautious figure as well as a hopeful one before you plan around a date.
Lean, Fat, Coast and Barista FIRE
FIRE has picked up several variants. None has an official definition, so the calculator uses common shorthand: Lean FIRE is 70% of your planned spending and Fat FIRE is 150%.
| Version | What it means | Target | Years |
|---|---|---|---|
| Lean FIRE | A frugal retirement on $35,000 a year | $875,000 | 15.8 |
| FIRE | Your planned spending, $50,000 a year | $1,250,000 | 20.8 |
| Fat FIRE | A comfortable cushion, $75,000 a year | $1,875,000 | 27.3 |
| Barista FIRE | $20,000 of part-time pay covers part of it | $750,000 | 13.9 |
| Coast FIRE | Enough now to grow to the full number by 65 | $277,852 | 6.9 |
Coast FIRE in detail
Coast FIRE is the point where you could stop saving altogether and your investments would still grow to your full FIRE number by a traditional retirement age. After that, your pay only has to cover your spending, which opens up lower-paid work, shorter hours or a career break.
The coast amount is the FIRE number discounted back at the real return. For $1,250,000 by 65 at a 4.39% real return, a 25-year-old needs about $224,137 invested, a 30-year-old about $277,852 and a 40-year-old about $426,985. In the worked example, saving $30,000 a year gets to the coast point in 6.9 years, at about 36.
Coasting relies on the return
Coast FIRE leans entirely on decades of growth. If returns disappoint you will reach 65 short, with no new savings to make up the gap. Many people keep saving something, even after they reach the coast point.
Barista FIRE in detail
Barista FIRE means leaving full-time work once your portfolio covers most of your spending, and earning the rest from part-time or freelance work. The name comes from the idea of a coffee-shop job with health benefits, though any part-time income counts.
Every dollar of part-time income cuts the FIRE number by 25 dollars at a 4% rate. In the example, $20,000 a year of part-time pay brings the target from $1,250,000 down to $750,000 and the time from 20.8 to 13.9 years. Part-time work in early retirement also keeps skills fresh and gives you an easy way to adjust if markets fall.
Where FIRE savers invest
Most FIRE plans fill tax-advantaged accounts first, then use a taxable brokerage account for the rest. In 2026 you can put $24,500 into a 401(k), $7,500 into an IRA and $4,400 ($8,750 for family cover) into a health savings account.
- Examples
- 401(k), traditional and Roth IRA, HSA
- Benefit
- Tax break on the way in or the way out
- Catch
- Rules on withdrawals before 59½
- Examples
- Index funds in an ordinary account
- Benefit
- Money available at any age
- Catch
- Dividends and gains are taxed
Getting money out before 59½
Withdrawals from a 401(k) or IRA before 59½ usually carry a 10% additional tax on top of income tax. FIRE plans use several routes around it:
- Roth IRA contributions: what you put into a Roth IRA can come out at any time, tax- and penalty-free. Only the earnings are locked up.
- Roth conversion ladder: money converted from a traditional IRA to a Roth can be withdrawn penalty-free five years after each conversion. Converting a year’s spending each year builds a ladder.
- The rule of 55: if you leave your job in or after the year you turn 55, withdrawals from that employer’s 401(k) avoid the 10% tax.
- Section 72(t) payments: a series of substantially equal periodic payments, worked out by an IRS method, avoids the 10% tax at any age, but you must keep them up for five years or until 59½, whichever is later.
- A taxable account: money in an ordinary brokerage account is available at any time, which is why many early retirees plan to live on it first.
Health insurance before Medicare
Medicare starts at 65. Leave work at 45 and you need 20 years of private cover. Options include a Marketplace plan at HealthCare.gov, a spouse’s employer plan, or COBRA for up to 18 months after leaving a job. Marketplace premium tax credits depend on income, so an early retiree with low taxable income may pay much less than the full premium.
Budget for it
Health insurance and out-of-pocket costs are the expense early retirees most often underestimate. Put a realistic premium into your retirement spending, using the "Retirement spending vs today" option if it is higher than now.
Taxes in early retirement
The calculator doesn’t take tax off withdrawals, so treat your spending figure as including any tax you expect to pay. In practice, early retirees often pay little federal tax. Living on Roth contributions and on long-term gains from a taxable account, which are taxed at 0% up to $49,450 of taxable income for a single filer in 2026 ($98,900 for married couples filing jointly), can keep the bill very low. Our capital gains tax calculator shows how much you can realize at 0%.
Bad markets early on
The order of returns matters once you start withdrawing. A fall in the first few years of retirement, while you are selling shares to live on, does far more damage than the same fall twenty years later. This is called sequence-of-returns risk, and it is the main reason the 4% rule sometimes fails.
Common defenses include a cash buffer of one to two years of spending, a lower starting withdrawal rate, part-time income in the early years, and spending less after a bad year. Reaching your number in a strong market is also a good moment to build in some extra margin.
Staying flexible
A FIRE date is a projection, not a contract. Returns will differ from your assumption, spending will change with family life, and tax and health rules will shift over the decades. Revisit the numbers once a year with your real balance. If you are ahead, you can bank the margin or retire sooner; if you are behind, small changes to spending or saving made early are much easier than big ones made late.
First steps
- Track a year of spending, so your FIRE number rests on real figures.
- Build an emergency fund, so a surprise bill doesn’t mean selling investments.
- Pay off high-interest debt such as credit cards; our debt payoff calculator compares methods.
- Take any 401(k) employer match in full, then fill a Roth or traditional IRA and an HSA if you have one.
- Invest the rest in low-cost, broad index funds and raise your savings with each pay rise.
Common mistakes
- Counting home equity in the FIRE number. You can’t spend your house unless you sell it or downsize.
- Using a nominal return with today’s spending, which makes the date look years earlier than it is.
- Using 4% for a 50-year retirement without any flexibility.
- Forgetting health insurance, home repairs, car replacements and taxes in retirement spending.
- Leaving no easy way to reach money before 59½.
Key numbers
| Item | Figure |
|---|---|
| FIRE number at a 4% withdrawal rate | 25 × yearly spending |
| FIRE number at 3.5% | About 28.6 × yearly spending |
| Real return at 7% with 2.5% inflation | 4.39% |
| 401(k) employee limit, 2026 | $24,500 |
| IRA limit, 2026 | $7,500 |
| HSA limit, 2026 (self / family) | $4,400 / $8,750 |
| Age for penalty-free 401(k) and IRA withdrawals | 59½ |
| Medicare starts | 65 |
| 0% long-term gains rate, 2026 (single / joint) | Up to $49,450 / $98,900 of taxable income |
Social Security and FIRE
Social Security is based on your 35 highest-earning years. Retiring early means fewer earning years and more zeros in the average, so your benefit will be smaller than if you had kept working, but it rarely disappears. Many FIRE plans treat it as a bonus that arrives in the 60s and lowers the withdrawals needed from then on. You can claim from 62 with a reduced benefit, or wait until 70 for a larger one.