FIRE Calculator - FIRE Number and Years to Retire Early

Your FIRE number and the year you could stop working

Twenty-five times your yearly spending: that is the FIRE number behind the 4% rule, and it is the first thing this FIRE calculator works out. The second is how long it takes to get there from where you are now, with your savings rate, your expected return and inflation taken out of it, year by year. Someone who takes home $80,000, spends $50,000 and has $50,000 invested needs $1,250,000 and reaches it in 24 years at a 7% return and 3% inflation.

Six fields, three of them optional

Yearly take-home income - after taxes, from all sources. Monthly take-home times 12, plus side income. For a couple, add both.
Yearly spending - what your life costs per year today. The difference between the two is your savings.
Current portfolio - retirement accounts, brokerage, savings meant for FIRE. Not the house you live in and not the car.
Expected return - nominal, before inflation. Empty means 7%. The calculator turns it into a real return itself.
Withdrawal rate (SWR) - the share of the portfolio you plan to take out each year. Empty means 4%.
Inflation - empty means 3%; a typed 0 is kept as zero. Then read the headline, the three tiles, the yearly table and the savings rate scenarios.

The route, one decision at a time

Know your spending, not your income. The target depends only on what you spend. $40,000 a year needs $1,000,000 at 4%; $60,000 needs $1,500,000, whatever you earn.

Pick a withdrawal rate that fits the length of retirement. 4% comes from 30-year periods. Retiring at 40 means planning for 50 years, where 3.25-3.5% is the safer range.

Work in real terms. The calculator divides, not subtracts: 1.07 / 1.03 - 1 = 3.9%. Every figure in the table is in today's dollars, so the target never has to be inflated.

Push the savings rate. It is the one lever that works on both ends: more goes in each year, and a smaller lifestyle needs a smaller portfolio.

4%, 3.5% or 3.25%: the FIRE number at four spending levels

Lean and fat FIRE have no official lines; they simply mean a small or a generous yearly budget. What matters is how much each extra $20,000 of spending and each step down in the withdrawal rate costs.

Yearly spending	SWR 4% (30 years)	SWR 3.5%	SWR 3.25% (50 years)
$40,000 (lean)	$1,000,000	$1,142,857	$1,230,769
$60,000	$1,500,000	$1,714,286	$1,846,154
$80,000	$2,000,000	$2,285,714	$2,461,538
$100,000 (fat)	$2,500,000	$2,857,143	$3,076,923

Verdict: for an early start, with 40 to 50 years of withdrawals ahead, plan on 3.25-3.5%. It adds 14-23% to the target, which is cheaper than running out at 75.

Where the 4% comes from: the Trinity Study (Cooley, Hubbard and Walz) found that a 4% first-year withdrawal, raised with inflation every year, lasted 30 years in 95% of past periods for a portfolio of half stocks, half bonds. Longer horizons were less forgiving, which is why the lower rates appear in the last column.

The formulas, run on four plans

FIRE number = yearly spending / SWR. Real return = (1 + return) / (1 + inflation) - 1. Each year the portfolio grows by the real return and the year's savings are added at the end; the first year it reaches the FIRE number is the answer.

$120,000 income, $60,000 spending, $100,000 invested. Savings rate 50.0%, FIRE number $1,500,000, real return 3.9%: 17 years.

$60,000 income, $40,000 spending, starting from zero, inflation set to 0. Real return equals the nominal 7.0%, FIRE number $1,000,000: 23 years.

$100,000 income, $40,000 spending, $250,000 invested, SWR 3.5%. Savings rate 60.0%, FIRE number $1,142,857: 11 years.

$70,000 income, $40,000 spending, $1,200,000 invested. Already past the $1,000,000 target: the result says FIRE is reached and the $40,000 a year means $3,333 a month.

The savings rate does most of the work. Starting from zero on $100,000 of take-home pay, with the default 7% return and 3% inflation:

Savings rate	Spending	FIRE number	Years to FIRE
30%	$70,000	$1,750,000	32
40%	$60,000	$1,500,000	24
50%	$50,000	$1,250,000	18
60%	$40,000	$1,000,000	14
70%	$30,000	$750,000	10
80%	$20,000	$500,000	6

One plan from the first deposit to the FIRE year

Take the plan from the top of this page: $80,000 take-home, $50,000 spending, $50,000 already invested, the default 7% return and 3% inflation. The calculator adds $30,000 at the end of every year and grows the balance by the real return of 3.9%. These are rows from its yearly table, all in today's dollars.

Year	Portfolio	Growth that year	Share of the target
0	$50,000	-	4%
1	$81,942	$1,942	7%
5	$222,604	$7,200	18%
10	$431,431	$15,007	35%
15	$684,080	$24,452	55%
20	$989,748	$35,878	79%
24	$1,279,858	$46,724	102%

Two things stand out. Growth is tiny at first: in year one the market adds $1,942, about a fifteenth of what you put in yourself. By year 18 the yearly growth ($31,045) passes the $30,000 you save, and from then on the portfolio does more of the work than your paycheck. Over the 24 years you deposit $720,000 on top of the starting $50,000; the remaining $509,858 of the final balance is growth.

Second, the last stretch is short. Going from 79% of the target to 102% takes four years, while the first 18% took five. That is why the scenario list often shows a big gain from a small change in the savings rate near the end.

Now change one input at a time and keep the rest of the plan:

Expected return 5% instead of 7%. The real return drops to 1.9% and the date moves from 24 to 30 years. The FIRE number does not change; only the speed does.

Spending $45,000 instead of $50,000. The savings rate rises to 43.8%, the target falls to $1,125,000, and FIRE comes in 20 years. Five thousand dollars a year buys four years.

Withdrawal rate 3.5% instead of 4%. The target grows to $1,428,571 and the date to 26 years. Two extra years is the price of planning for a 40-year retirement instead of a 30-year one.

Of the three, cutting spending is the only one fully in your hands, and it is also the strongest. Returns are a guess about the future; the withdrawal rate is a choice about risk; spending is a number you can check on your bank statement next month.

Where FIRE plans quietly go wrong

Mistake: subtracting inflation from the return. 7% minus 3% is 4%, but the real return is 3.9%. Over 20 years the shortcut overstates growth. Better: let the calculator divide.

Mistake: using 4% for a 50-year retirement. The 95% figure belongs to 30-year periods. Better: 3.25-3.5% when you stop in your thirties or forties.

Mistake: counting the home you live in. It does not pay for groceries unless you sell it. Better: count only assets you would draw from.

Mistake: planning on today's spending with no health insurance line. Before Medicare age, coverage you used to get through work becomes a bill. Better: add it to yearly spending before you read the FIRE number.

Mistake: treating the FIRE number as money you can spend in full. Withdrawals from a traditional 401(k) or IRA are taxed as income, so $50,000 of withdrawals buys less than $50,000 of life. Better: enter yearly spending including the tax you expect to pay on withdrawals, and the target grows to match.

FIRE questions, answered with the arithmetic

How do I calculate my FIRE number?

Divide yearly spending by the withdrawal rate. At 4% that is spending x 25: $50,000 becomes $1,250,000. At 3.5% the same spending needs $1,428,571.

Does this FIRE calculator include inflation?

Yes. It projects the portfolio with the real return, so every amount in the yearly table is in today's dollars and can be compared directly with the FIRE number. Type 0 for inflation to see nominal growth instead.

How do I use it as a couple?

Add both take-home incomes, the household's spending and both portfolios. The FIRE number is for the household; $80,000 of shared spending needs $2,000,000 at 4%.

What about Social Security or a pension?

This calculator does not add them. A rough way to include a later benefit is to lower yearly spending by the amount it will cover, keeping in mind that it starts years after an early retirement.

What is the difference between lean, fat and coast FIRE?

Lean and fat describe the budget: a small one needs a smaller FIRE number, a generous one a bigger number. Coast FIRE means you already have enough invested to grow into a traditional retirement on its own, so you only need to cover current costs. This calculator answers the full FIRE question; the yearly table shows how much the portfolio grows without new savings each year in the Growth column.

How much do I need to retire early on $40,000 a year?

$1,000,000 at the 4% rule, $1,142,857 at 3.5% and $1,230,769 at 3.25%. The lower figures are the ones to aim for when retirement may last 40 years or more. How long it takes depends on your savings: on $100,000 of take-home pay with $40,000 of spending and nothing invested yet, the calculator says 14 years at the 4% rule.