FIRE Calculator

How to use the FIRE calculator

FIRE stands for financial independence, retire early. The idea is simple: once your investments are large enough that you could pay your living costs from them indefinitely, work becomes optional. This FIRE calculator works out how large that is (your FIRE number) and how long your current plan would take to get there. It opens with an example plan already filled in: a 30-year-old with $50,000 invested, spending $40,000 a year and saving $25,000 a year, with an example 7% return, 3% inflation and a 4% withdrawal rate. Those rates are illustrations, not forecasts. Replace them with your own numbers and everything updates as you type.

1. Enter your age and what you have invested now. Count retirement accounts, brokerage accounts and other investments you would live from. Leave out your home and emergency fund unless you would sell or spend them.
2. Enter what you spend and what you save in a year. Spending sets the target; savings set the speed. The tool works out your savings rate from the two.
3. Choose a return and an inflation rate. The expected return is a yearly average before inflation. The calculator turns it into a real return, after inflation and any fees, and does all the math in today's dollars.
4. Pick a withdrawal rate. 4% is the classic rule of thumb; 3% or 3.5% is more cautious for a retirement that could last 40 years or more. Tap a chip or type your own.
5. Read the results. You get your FIRE number, the time and age at which you would reach it, your savings rate, a growth chart and a year-by-year table. Copy the results, download the table as a CSV file or print it.

Three more tabs answer the follow-up questions. FIRE types shows your targets for Lean FIRE, Fat FIRE, Barista FIRE and Coast FIRE, so it doubles as a coast FIRE calculator. Savings rate shows how many years each savings rate from 5% to 90% would take. What if puts your plan next to two variations, such as spending less or planning on a lower withdrawal rate, and shows how much sooner or later each one gets there.

How to calculate your FIRE number

Your FIRE number is the portfolio that could fund your yearly spending at a chosen withdrawal rate. The withdrawal rate is the share of the portfolio you take out in the first year of retirement; in the classic version of the rule, later withdrawals rise with inflation.

FIRE number   = yearly spending in retirement ÷ withdrawal rate
multiple      = 1 ÷ withdrawal rate             4% → 25×, 3.5% → 28.57×, 3% → 33.33×
savings rate  = yearly savings ÷ (yearly savings + yearly spending)

At a 4% withdrawal rate the multiple is 25, which is where the "25x rule" comes from: multiply what you spend in a year by 25. With the example spending of $40,000, that is $1,000,000. The withdrawal rate moves the target a lot, so it is worth seeing the range:

Use the spending you expect in retirement, not today's spending, if the two will differ. Some costs stop when you stop working (commuting, retirement contributions, possibly a mortgage), and some start (health insurance, more travel). The Spending in retirement field under More assumptions handles that. Count taxes on your withdrawals as part of spending.

The 4% rule: where it comes from, and its limits

The 4% figure comes from research on how much retirees could have withdrawn in the past without running out of money, not from a law of nature. Two studies are usually cited.

Bengen, 1994. Financial planner William Bengen tested retirements starting every January from 1926 onward, using historical returns for a portfolio of stocks and intermediate-term Treasury notes, with a first-year withdrawal set as a share of the portfolio and later withdrawals raised for inflation. With a 4% starting withdrawal, he found that "no client enjoys less than about 35 years" before the money ran out, and that 3% to about 3.5% lasted at least 50 years in every period he tested. He recommended holding between 50% and 75% in stocks, and he assumed the money sat in tax-deferred accounts ("Determining Withdrawal Rates Using Historical Data," Journal of Financial Planning, October 1994, reprinted by the Financial Planning Association).

The Trinity study, 1998. Three Trinity University professors, Philip Cooley, Carl Hubbard and Daniel Walz, ran overlapping payout periods from 1926 to 1995 with the S&P 500 for stocks and long-term high-grade corporate bonds. A period counted as a success if the portfolio still had more than $0 at the end. They note that "the study did not adjust for taxes or transaction costs." With withdrawals raised for inflation every year, their 30-year results were ("Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable," AAII Journal, February 1998, Table 3):

Read those numbers with their limits in mind:

• The horizon was 30 years. Someone who stops working at 40 may need their money for 50 years or more. The Trinity authors' own conclusion was that "early retirees who anticipate long payout periods should plan on lower withdrawal rates."
• It is one country's past. The data are U.S. markets over a period that turned out well for U.S. stocks. Nothing says the future will look the same.
• Fees and taxes were left out. A 1% yearly fee takes a large bite out of a 4% withdrawal. Add fees in the calculator and plan for taxes on withdrawals.
• "Success" can mean ending with almost nothing, and it assumes you never cut spending in a bad year. In practice many people adjust, which helps, and both studies expected some mid-course correction.

So treat 4% as a starting point for planning, not a promise. If your retirement could be long, testing 3% or 3.5% in the calculator shows what a more cautious plan costs in extra years.

How long until you reach financial independence

The time to FI depends on four things: what you already have, what you add each year, the real return, and the target. The calculator grows your balance month by month, adding one twelfth of your yearly savings at the end of each month, and finds the first month in which the balance reaches your FIRE number. With a starting balance P, yearly savings C, real yearly return r and target T:

monthly rate     i = (1 + r)^(1/12) − 1
balance after m  B(m) = P × (1 + i)^m + (C ÷ 12) × ((1 + i)^m − 1) ÷ i
months to FI     m = ln((T × i + C ÷ 12) ÷ (P × i + C ÷ 12)) ÷ ln(1 + i), rounded up

Worked example: the default plan

A 30-year-old has $50,000 invested, spends $40,000 a year and saves $25,000 a year. Expecting a 7% return with 3% inflation gives a real return of (1.07 ÷ 1.03) − 1 = 3.88%. The FIRE number at 4% is $1,000,000, and the savings rate is 38.5%. The balance first passes the target after 22 years, 5 months, at age 52. By then, at 3% inflation, the same target would read about $1,939,848 in future dollars, which is why the calculator keeps everything in today's dollars: $1,000,000 means what $1,000,000 buys now.

Example 2: a later start and a cautious withdrawal rate

A 38-year-old has $180,000 invested, spends $50,000 a year and saves $45,000, a savings rate of 47.4%. Planning on a 6.5% return, 2.5% inflation (a 3.90% real return) and a cautious 3.5% withdrawal rate puts the FIRE number at $1,428,571, 28.57 times spending. On those assumptions the plan gets there in about 17 years, 1 month, at age 55. At 4% instead, the target drops to $1,250,000 and the wait to 15 years, 3 months.

Small changes add up. In the default plan, a 1% yearly fee lowers the real return to 2.91% and stretches the wait to 24 years, 9 months. Planning to spend $30,000 in retirement instead of $40,000 cuts the target to $750,000 and the wait to 18 years, 2 months.

Why your savings rate matters most

Your savings rate works twice: every dollar you don't spend is a dollar invested, and it is also a dollar your FIRE number doesn't have to cover. If you start from zero, your income drops out of the math completely and the time to FI depends only on the savings rate, the real return and the withdrawal rate. This table uses the example 3.88% real return and a 4% withdrawal rate. The last column starts from the example's $50,000 with take-home pay of spending plus savings.

Going from a 10% to a 20% savings rate saves almost two decades; going from 50% to 60% saves a few years. That is why people chasing early retirement focus on the gap between income and spending before they worry about squeezing an extra fraction of a percent out of their investments. The Savings rate tab redraws this table with your own return and withdrawal rate.

Real vs. nominal returns, and inflation

A nominal return is what an account statement shows. A real return is what is left after inflation, which is what actually grows your buying power. Because your FIRE number is a list of things you want to be able to buy, the calculator converts your expected return into a real return and works in today's dollars throughout:

real return = (1 + nominal return − fees) ÷ (1 + inflation) − 1

A 7% nominal return with 3% inflation is a 3.8835% real return, a little less than the 4 points you get by simply subtracting. If you would rather think in real terms from the start, set inflation to 0% and enter a real return directly. The U.S. Bureau of Labor Statistics publishes the Consumer Price Index, the usual measure of inflation; the 3% in the example is an illustration, not a forecast.

Compound growth is the engine of every FIRE plan, and it is sensitive to the rate. The SEC's investor education site explains the Rule of 72: divide 72 by the yearly return to estimate how many years money takes to double. At a 4% real return that is about 18 years; at 6%, about 12. No one knows the future return, which is why the What if tab is useful: try a lower return and see how sensitive your date is. Returns depend heavily on how you invest; Investor.gov's guide to asset allocation and diversification covers how the mix of stocks, bonds and cash changes both risk and return.

Lean FIRE, Fat FIRE, Barista FIRE and Coast FIRE

These names come from the FIRE community and have no official definitions or dollar thresholds. What they share is the FIRE number formula; what changes is the spending the portfolio has to cover, or when it has to cover it. The examples below use the default plan.

• Lean FIRE means reaching independence on a frugal budget. Covering $30,000 a year takes $750,000, reached in about 18 years, 2 months at age 48. A lean budget leaves less room for surprises such as medical bills or a roof replacement.
• Fat FIRE means a generous budget and a bigger cushion. Covering $80,000 a year takes $2,000,000, about 34 years, 10 months away, at age 64 on the same savings.
• Barista FIRE means leaving your career once your savings cover what part-time or lower-stress work doesn't. With $20,000 a year of part-time pay, savings only need to cover the rest, so the target is $500,000, reached in about 13 years at age 43. The name comes from the idea of a part-time job that also offers health insurance.
• Coast FIRE means you have enough invested that, without adding another dollar, it should grow to your full FIRE number by a later age, so your paycheck only has to cover your current spending. The coast number is the FIRE number discounted by the real return: target ÷ (1 + r)^{years to go}. To coast to $1,000,000 by age 65, a 30-year-old would need $263,555 invested today; saving as in the example, they would reach that point in about 10 years, 5 months, at age 40.

The FIRE types tab shows all five targets for your own plan. Coast and Barista FIRE both depend on continuing to earn something, so a job loss or a long illness affects them more than a fully funded plan.

Sequence of returns risk

This calculator, like most FIRE calculators, assumes the same return every year. Real markets don't work that way, and once you start withdrawing, the order of returns matters as much as their average. A loss in the first years of retirement forces you to sell more of a shrunken portfolio to pay the bills, and those shares are not there for the recovery.

Here is a simple illustration. Two retirees each start with $1,000,000 and withdraw $40,000 at the start of every year. Both get the same seven yearly real returns, −15%, −10%, 5%, 12%, 15%, 10% and 8%, but the second retiree gets them in reverse order. The average is identical. The ending balances are not:

That is the risk the historical studies capture and a constant-return calculator cannot. People manage it with a lower withdrawal rate, a cash or bond reserve for the first years, flexible spending they can cut in a bad market, or part-time income early on. None of those show up in a single "years to FI" figure, so leave yourself a margin.

Social Security and your FIRE number

The calculator leaves Social Security out, which is the cautious choice: your portfolio covers everything. In reality most workers will get a benefit later in life, and it lowers what the portfolio has to cover from that age on. For people born in 1960 or later, full retirement age is 67, and starting benefits at 62 reduces them by about 30%, according to the Social Security Administration. Retiring early also means fewer years of earnings in your benefit record, so an estimate made while you are still working may overstate what you would get. You can see your own earnings record and estimates in a my Social Security account.

A simple way to account for it is to treat a benefit as a safety margin rather than part of the plan. A more detailed one is to plan two stages: a bridge from your FI date to the age you claim, and a smaller target afterwards. This tool doesn't model the stages, so if you lower your retirement spending to reflect a benefit, remember that the lower figure only applies from the claiming age.

Taxes and getting at retirement money early

Your FIRE number should cover the taxes on your withdrawals, so include them in your retirement spending. How much depends on the type of account: withdrawals from traditional pre-tax accounts are taxed as income, while long-term gains in a taxable brokerage account and qualified Roth withdrawals are treated differently.

Early retirees also have to think about timing. Distributions from a 401(k) or similar plan before age 59½ generally owe a 10% additional tax on the taxable part, with exceptions, including leaving your employer in or after the year you turn 55 (IRS Topic 558). IRAs have their own version of the rule (IRS Topic 557). One exception many early retirees use is a series of substantially equal periodic payments, which comes with strict rules about changing the payments. The IRS keeps a full list of exceptions to the tax on early distributions. Many people bridge the gap with a taxable account. The rules are detailed, so check them, or a tax professional, before you rely on them.

Health insurance before Medicare

Medicare is health insurance for people 65 or older, and for some younger people with certain disabilities or conditions (Medicare.gov). If you stop working at 45, you need another way to cover the 20 years in between, such as a plan from the HealthCare.gov marketplace, a spouse's employer plan or part-time work with benefits. Premiums and out-of-pocket costs can be a large line in an early retiree's budget, so put a realistic figure for them into your retirement spending before you trust your FIRE number.

FIRE calculator vs. retirement calculator

A traditional retirement calculator usually starts from a fixed retirement age, such as 65, and asks whether your savings will last from then until the end of your life, often with Social Security and a pension included. A FIRE calculator turns the question around: given what you spend and save, when could you stop needing a paycheck? Both run on the same compound interest math. If you only want to see how a lump sum and monthly deposits grow, a compound interest calculator or savings calculator, such as the one on Investor.gov, does that. If you want to know which accounts to fill first, a 401k calculator or Roth IRA calculator answers that better. This tool is for the "how much is enough, and how long" question.

How we calculate

Every figure in the tool and on this page comes from the same code, and the examples above are checked against it automatically. The assumptions:

• Today's dollars. Spending, savings, balances and the FIRE number are in today's dollars. The schedule also shows each balance in future dollars, grown by your inflation rate.
• A constant real return. Real return = (1 + return − fees) ÷ (1 + inflation) − 1, the same every year. There are no market swings, so there is no sequence risk in the results.
• Monthly deposits. Yearly savings ÷ 12 is added at the end of each month, and it rises with inflation, so it stays the same in today's dollars. The month rate is (1 + r)^1/12 − 1, so twelve months compound to exactly one year's return.
• Whole months. The time to FI is the first whole month in which the balance reaches the target. The age shown is your age now plus that time, rounded down.
• Withdrawal rate. The FIRE number is retirement spending ÷ withdrawal rate. The tool does not simulate retirement itself.
• Not included: taxes, Social Security, pensions, home equity, one-off expenses, changes in income, and anything after your FI date. Plans that would take more than 100 years are shown as not reached.

Your numbers stay on your device

Your savings and spending are personal. Every calculation on this page runs as JavaScript in your own browser tab, and there is no server doing the math.

• Nothing is uploaded. The tool has no code that sends data anywhere, and the page's Content-Security-Policy only allows connections back to this site. Open your browser's developer tools, choose the Network tab and change a few numbers: no request appears.
• It keeps working offline. Once the page has loaded, you can disconnect and keep calculating.
• No account, no cookies. The tool remembers your last inputs and tab in your browser's local storage, on your device only.

Sources

• William P. Bengen, "Determining Withdrawal Rates Using Historical Data", Journal of Financial Planning, October 1994 (Financial Planning Association reprint).
• Philip L. Cooley, Carl M. Hubbard and Daniel T. Walz, "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable", AAII Journal, February 1998 (the Trinity study).
• SEC Investor.gov: Compound interest calculator, What is compound interest? and Asset allocation and diversification.
• U.S. Bureau of Labor Statistics: Consumer Price Index.
• Social Security Administration: Retirement benefits by year of birth and early-claiming reduction and my Social Security.
• IRS Topic 558: Additional tax on early distributions from retirement plans other than IRAs and Topic 557: Additional tax on early distributions from traditional and Roth IRAs.
• IRS: Substantially equal periodic payments and Retirement topics: Exceptions to tax on early distributions.
• Medicare.gov: Get started with Medicare and HealthCare.gov.

Reviewed by microplugins · Last updated October 12, 2026

This is an educational tool, not financial, investment or tax advice. Returns, inflation and withdrawal rates on this page are examples, not forecasts, and past market results do not guarantee future ones. For decisions about your own money, consider a qualified, fee-only professional.