How to use this FIRE calculator
- Enter your age, take-home pay, yearly spending and what you have invested today. Pick "A couple" to plan as a household.
- If you will spend differently in retirement, turn that on. Add Social Security or a pension if you want them counted.
- Check the assumptions (return, inflation, fees, withdrawal rate and plan age), then read your FI age, milestones and risk tests.
Take-home pay means pay after tax but before any 401(k) or IRA contributions, so the calculator can treat everything you don't spend as savings. Everything is in today's dollars, and your inputs stay in the page link, so you can bookmark a scenario or share it.
What is FIRE?
FIRE stands for Financial Independence, Retire Early. The idea traces back to Your Money or Your Life by Vicki Robin and Joe Dominguez, first published in 1992 and still considered a core text of the movement[1]. You save and invest a large share of your income until your investments can cover your living costs, then work becomes optional. The usual target is 25 times your yearly spending[2]. Our guide to what FIRE is covers the movement and its variations in more depth.
How does the FIRE calculator work?
The calculator answers two questions: how much you need, and when your savings get there.
FIRE number = annual retirement spending ÷ safe withdrawal rate. The 4% withdrawal rate comes from William Bengen's 1994 study, which found a 4% inflation-adjusted withdrawal lasted at least 33 years in every period he tested[3]. The Trinity study later found 4% withdrawals succeeded in 95%-98% of 30-year periods for stock-heavy portfolios[4].
Then it projects your portfolio year by year: last year's balance grows at your real return, and your savings are added at year end. Your FI age is the first year the balance reaches the FIRE number for retiring that year. If you count Social Security or a pension, the FIRE number depends on the age you retire, because retiring earlier means more years before that income starts.
Worked example: when can Jordan retire?
Jordan is 32, takes home $95,000, spends $50,000 and has $120,000 invested. That leaves $45,000 a year to invest, a 47% savings rate. With 7% returns, 3% inflation and 0.1% fees, the real return is 3.79%.
- FIRE number: $50,000 ÷ 4% = $1,250,000
- Jordan's balance first passes that at age 49, 17 years from now.
- On the way, Jordan reaches Coast FI at 39 (enough to stop saving and still reach full FI by 65), Half FI at 41 and Lean FI at 46. Saving at the same pace, Fat FI (150% of the number) arrives at 55.
What does the FIRE calculator show?
- FI age. The first age your projected balance covers your retirement spending at your withdrawal rate. This is the "when" answer, and it moves a lot with small changes, so read it together with the what-if table.
- FIRE number and progress. The portfolio you need, as a multiple of spending, and how far along you are today.
- Milestones. Coast FI, Half FI, Lean FI (75% of the number), full FI and Fat FI (150%). Coast FI matters most for people who want to keep working but stop saving; the Coast FIRE calculator goes deeper on it.
- Path chart. Your balance each year in today's dollars, rising while you save and drawn down in retirement.
- What-if table. One change at a time: more savings, less spending, a better return or a lower withdrawal rate.
- Savings rate curve. Years to FI at every savings rate from 5% to 90%, starting from what you have invested today.
- Risk tests. A Monte Carlo simulation and a replay of every historical start year, both described below.
What would change your FI age?
Spending is the strongest lever, because a cut both raises your savings and lowers the target. Here is the calculator's what-if table for Jordan, one change at a time:
| If Jordan… | FI age | Change |
|---|---|---|
| Invest $250 more a month | 49 | No change |
| Invest $500 more a month | 48 | 1 year sooner |
| Spend 10% less, now and in retirement | 47 | 2 years sooner |
| Earn 1% more a year on investments | 48 | 1 year sooner |
| Use a 3.5% withdrawal rate | 51 | 2 years later |
Our calculation with the calculator's engine; everything else as in the example.
Cutting spending by 10% brings FI forward to 47, more than investing an extra $500 a month does (FI at 48). Switching to a more cautious 3.5% withdrawal rate pushes it out to 51, which is the price of a plan built for a longer retirement. Small changes can show "No change" because the calculator works in whole years.
What is your FIRE age, and what sets it?
Your FIRE age (or FI age) is the age at which work becomes optional. Four inputs set it: your savings rate, what you already have invested, your real return and your withdrawal rate. Of these, the savings rate matters most, because it does double duty: it sets how fast you build wealth and how much you need. Mr. Money Mustache's well-known table shows that, with 5% real returns and a 4% withdrawal rate, a 10% savings rate means roughly 51 years of work, while 50% means about 16[6]. Our engine gives the same answers and shows how they shift with the calculator's more cautious default return:
| Savings rate | 5% real, 4% SWR | 3.8% real, 4% SWR | 3.8% real, 3.5% SWR |
|---|---|---|---|
| 10% | 51.3 years | 60.6 years | 63.9 years |
| 20% | 36.7 years | 42.1 years | 45.0 years |
| 30% | 28.0 years | 31.4 years | 33.9 years |
| 40% | 21.6 years | 23.8 years | 25.9 years |
| 50% | 16.6 years | 17.9 years | 19.7 years |
| 60% | 12.4 years | 13.2 years | 14.6 years |
| 70% | 8.8 years | 9.2 years | 10.2 years |
Our calculation: years to financial independence starting from nothing invested, with spending equal to take-home pay minus savings.
Two things stand out. Going from a 10% to a 30% savings rate saves more working years than going from 50% to 70%, so the first increases matter most. And the assumptions matter: at the default return, a 50% saver needs about 1.3 more years than the classic table suggests. Money already invested shortens all of these; the calculator's curve starts from your real balance. Try the savings rate calculator to work out your rate from your paycheck.
What return and withdrawal rate should I assume?
The default 7% nominal return sits between history and today's forecasts. US stocks returned 10.0% a year from 1928 to 2025[7], while Vanguard's 10-year forecast for US stocks is 4.8%-6.8%[8]. For withdrawal rates, 4% fits a 30-year retirement. If you retire in your 30s or 40s, research on 50-60 year horizons points to 3.25%-3.5%[5]. The FIRE number calculator shows how often each rate from 3% to 5% has lasted over your exact horizon, and the safe withdrawal rate calculator lets you search for the rate that fits your plan.
Will your FIRE plan work? Checking it against history
An average return hides the order returns arrive in. A bad decade at the start of retirement does far more damage than the same decade later, because you are selling investments while prices are low[9]. So the calculator runs two tests on 1928-2025 US stock, bond and inflation data[7]: 2,000 Monte Carlo lifetimes built from randomly drawn historical years, and a replay of your retirement starting in every year with a complete history.
For Jordan, retiring at 49 with 80% stocks and 0.1% fees, the replay of history lasted to 95 in 85% of start years, and 85% of the Monte Carlo lifetimes never ran out. That is lower than the 95%-98% the Trinity study found, because Jordan's retirement lasts 46 years, not 30. Working a little longer helps fast, because each year adds savings and growth and shortens the retirement:
| Retire at | Balance then | Historical success | If returns average 3.8% |
|---|---|---|---|
| 49 | $1,272,751 | 85% | 51% |
| 50 | $1,365,943 | 93% | 57% |
| 51 | $1,462,663 | 100% | 65% |
| 52 | $1,563,045 | 100% | 73% |
| 54 | $1,775,356 | 100% | 93% |
Our calculation: share of retirement start years since 1928 in which spending $50,000 a year lasted to 95. The last column shifts every historical year so the average real return equals our default, keeping the good and bad sequences.
Retiring at 51 with $1,462,663 survived every historical start year. If future returns are lower than history, as current forecasts suggest, the last column is the more sober guide. A success rate of 90% or more is a common comfort level. Below that, the usual fixes are a lower withdrawal rate, a few more working years, some part-time income, or a willingness to trim spending after bad years.
Should you include Social Security in your FIRE plan?
Counting it lowers your FIRE number and brings your FI age forward, but early retirees should count it with care. Full retirement age is 67 for anyone born in 1960 or later, claiming at 62 cuts the benefit by 30%, and waiting to 70 adds 24%[10]. Benefits depend on your earnings record, and workers with 35 or more years of covered earnings lose little by stopping early[10]. A FIRE career is often much shorter than that, so use an estimate based on the years you will actually work[11], and consider counting only part of it.
If Jordan counts a $20,000 benefit from 67, the FI age moves from 49 to 47, with a FIRE number of $1,050,667. The catch is that retiring earlier means a longer retirement with more years funded entirely by the portfolio, and that plan lasted in 76% of historical start years. Counting only 75% of the benefit ($15,000) gives FI at 48 and 88%. Turn the benefit on in the calculator and watch the risk tests, not just the FI age.
How do couples use the FIRE calculator?
Choose "A couple" and enter household numbers: combined take-home pay, combined spending and all invested assets. Use the younger partner's age, so the plan lasts until the younger of you reaches the plan age. If you both expect Social Security, add the two benefits together. If one of you earned little, the spousal benefit can be up to 50% of the other's benefit at full retirement age, and a surviving spouse can receive up to 100% of the deceased worker's benefit[10]. So a one-earner couple whose earner has a $26,667 benefit could count about $40,000 together, but the household drops back to the larger single benefit after one death.
Example: Alex and Sam are 35 and 37. They take home $160,000, spend $90,000, have $250,000 invested and expect $40,000 a year of combined Social Security from 67.
| Plan | FI age | FIRE number | Historical success |
|---|---|---|---|
| Ignore Social Security, 4% | 54 | $2,250,000 | 93% |
| Count $40,000 of Social Security from 67, 4% | 50 | $1,790,111 | 74% |
| Ignore Social Security, 3.5% | 56 | $2,571,429 | 100% |
| Count Social Security, 3.5% | 52 | $1,948,389 | 98% |
Our calculation: ages are the younger partner's, money lasting to 95, 80% stocks, raw history minus 0.1% fees.
Counting Social Security at 4% gets them there earliest, at 50, but with the weakest history (74%). Counting it at 3.5% lands at 52, still 2 years sooner than ignoring it at 4%, with 98% historical success. Pairing guaranteed income with a lower withdrawal rate is often the better trade.
What mistakes make a FIRE calculator wrong?
- Entering gross pay. Use take-home pay; otherwise taxes look like savings and your FI age arrives years too early.
- Counting 401(k) contributions twice. Enter pay before retirement contributions and leave them out of spending; the calculator counts everything you don't spend as invested.
- Mixing today's and future dollars. The calculator works in today's dollars. Don't compare its FIRE number with a projection from an account website that adds inflation.
- Forgetting health insurance before 65. Medicare starts at 65[13], and the end of the enhanced ACA subsidies brought back the subsidy cliff at 400% of the poverty level[14]. Add premiums to your retirement spending.
- Ignoring when you can reach the money. Withdrawals from retirement accounts before 59½ usually owe a 10% additional tax, with exceptions such as the Rule of 55 and 72(t) payments[12]. The early retirement calculator sizes the bridge from taxable accounts.
- Treating the FI age as a promise. It assumes a steady return every year. Read the risk tests and keep a margin.
How is a FIRE calculator different from a retirement calculator?
A traditional retirement calculator starts from a retirement date, usually in your 60s, and asks whether your savings will be enough by then. A FIRE calculator turns the question around: it starts from your savings rate and solves for the earliest age you could stop. Three things follow from that. It has to plan for a retirement of 40 to 60 years, so it treats the withdrawal rate as a choice, not a constant. It cares about the years before Social Security, Medicare and penalty-free access to retirement accounts, which a retirement at 67 never has to fund. And because the answer is an age, small changes in spending or savings show up as years gained or lost, which is the most useful way to judge a budget decision.
If you already know when you want to stop, the retirement calculator or how much do I need to retire fits better. If you want to keep working but stop saving, use the Coast FIRE calculator; for part-time work, the Barista FIRE calculator; for a very lean or a large budget, the Lean FIRE and Fat FIRE calculators.
Types of FIRE
FIRE comes in several flavors depending on how much you plan to spend and whether you plan to keep some work. Each has its own calculator.
| Type | Annual spending | What it means |
|---|---|---|
| Lean FIRE | Under about $40,000 | Very frugal budget, often in a low-cost area |
| FIRE | About $40,000-$80,000 | Portfolio covers a typical lifestyle |
| Chubby FIRE | About $80,000-$120,000 | Comfortable, some luxuries |
| Fat FIRE | $120,000+ | No meaningful budget constraints |
| Coast FIRE | Any | Saved enough to stop investing; work covers current bills |
| Barista FIRE | Any | Part-time income covers part of spending |
Spending bands are this site's rough conventions, not official definitions; they shift with inflation and cost of living.