acalculator

When can I retire early with FIRE?

Enter what you will spend each year, what you have invested, and what you save. See your FIRE number and the age you could reach financial independence.

Your numbers

Returns are never guaranteed.
The 4% rule is common. Lower is more cautious.
You reach financial independence at age
54.9

Spending $50,000.00 a year needs $1,250,000.00 at a 4% withdrawal rate; saving $2,000.00 a month, you reach it at age 54.9.

Years to go
24.9
Your FIRE number
$1,250,000.00
How far you are
8%
You’ll save
$598,000.00
Real growth
$556,583.33
Months
299

You reach financial independence at age: 54.9. Spending $50,000.00 a year needs $1,250,000.00 at a 4% withdrawal rate; saving $2,000.00 a month, you reach it at age 54.9.

How close are you to your FIRE number?

What does each year look like?

The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use

How to calculate

Computes your FIRE number (yearly spending ÷ withdrawal rate) and how long it takes to reach it from your savings and what you save, at a real return.

Example with the default inputs (Your age 30, Yearly spending in retirement $50,000.00, Invested today $100,000.00, You save $2,000.00, Expected yearly return 7%, Prices rise each year by 3%, Safe withdrawal rate 4%): Spending $50,000.00 a year needs $1,250,000.00 at a 4% withdrawal rate; saving $2,000.00 a month, you reach it at age 54.9.

Method: FIRE number = yearly spending ÷ withdrawal rate; each month, in today’s money, balance = balance × (1 + i) + savings, with i = ((1 + R) ÷ (1 + inflation))^(1/12) − 1, until the balance reaches the FIRE number.

  • All amounts are in today’s money: your savings and spending rise with prices.
  • The return and inflation stay the same every year. Real returns go up and down.
  • Savings are added at the end of each month.
  • The withdrawal rate is a rule of thumb from past market returns, not a guarantee that the money lasts.
  • Taxes, fees, and Social Security are not included.
  • This is an estimate for planning, not financial advice.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Your age 30, Yearly spending in retirement $40,000.00, Invested today $40,000.00, You save 3,000, Expected yearly return 0%, Prices rise each year by 0%, Safe withdrawal rate 4% gives Your FIRE number $1,000,000.00, Years to go 26.666667, You reach financial independence at age 56.666667, How far you are 4%, You’ll save $960,000.00.Source: hand calculation in content.mdx: 40,000 ÷ 0.04; (1,000,000 − 40,000) ÷ 3,000 = 320 months
  2. Your age 30, Yearly spending in retirement $50,000.00, Invested today $100,000.00, You save $2,000.00, Expected yearly return 7%, Prices rise each year by 3%, Safe withdrawal rate 4% gives Your FIRE number $1,250,000.00, Years to go 24.916667, You reach financial independence at age 54.916667.Source: month by month at the real return in content.mdx; checked in Python
  3. Your age 45, Yearly spending in retirement $60,000.00, Invested today $2,000,000.00, You save $0.00, Expected yearly return 5%, Prices rise each year by 3%, Safe withdrawal rate 4% gives Your FIRE number $1,500,000.00, Years to go 0, You reach financial independence at age 45.Source: hand calculation in content.mdx: $2,000,000 is already above 60,000 ÷ 0.04
  4. Your age 30, Yearly spending in retirement $50,000.00, Invested today $0.00, You save $100.00, Expected yearly return 0%, Prices rise each year by 0%, Safe withdrawal rate 4% gives Reached by age 100? Not by age 100, Your FIRE number $1,250,000.00.Source: hand calculation in content.mdx: 840 months × $100 = $84,000, far below $1,250,000
  5. Your age 30, Yearly spending in retirement $12,000.00, Invested today $100,000.00, You save $2,000.00, Expected yearly return 2%, Prices rise each year by 5%, Safe withdrawal rate 4% gives Your FIRE number $300,000.00, Years to go 11.083333, You reach financial independence at age 41.083333.Source: hand calculation in content.mdx: a negative real return, n = ln((F × i + S) ÷ (B × i + S)) ÷ ln(1 + i) = 132.8

How it is worked out

FIRE number = yearly spending ÷ safe withdrawal rate (as a decimal).

Everything runs in today’s money. The monthly real rate is

i = ((1 + R) ÷ (1 + inflation))^(1/12) − 1

where R is the yearly return and inflation the yearly inflation rate (as decimals). A yearly saving is split into 12 monthly amounts.

Starting from what you have invested today, each month:

  1. Growth = balance × i is added.
  2. Your monthly saving is added at the end of the month.

This stops at the end of the first month in which the balance reaches the FIRE number, or at age 100. If you already have the FIRE number today, it takes 0 months.

The results:

  • Years to go = the months it takes ÷ 12, and you reach financial independence at age = your age + years to go. If the balance does not reach the FIRE number by age 100 (12 × (100 − your age) months), these are left out and "Not by age 100" is shown instead.
  • How far you are = what you have invested today ÷ the FIRE number, as a percent.
  • You’ll save = your monthly saving × the months. Real growth adds each month’s growth.

The same count can be written as a formula: the balance after n months is B × (1 + i)^n + S × ((1 + i)^n − 1) ÷ i, so n is the first whole number at or above ln((F × i + S) ÷ (B × i + S)) ÷ ln(1 + i).

Assumptions

  • Savings and spending rise with prices, and the return and inflation stay the same every year.
  • The withdrawal rate is a rule of thumb, not a promise that the money lasts.
  • Taxes, fees, and Social Security are not included.
  • This is an estimate for planning, not financial advice.

Worked examples by hand

$40,000 a year, 4%, $40,000 invested, $3,000 a month, no growth, age 30. FIRE number = 40,000 ÷ 0.04 = $1,000,000. You are 40,000 ÷ 1,000,000 = 4% there. You need 960,000 ÷ 3,000 = 320 months = 26.7 years, so you reach it at 56.7, after saving $960,000.

$50,000 a year, 4%, $100,000 invested, $2,000 a month, 7% return, 3% inflation, age 30. FIRE number = $1,250,000. i = (1.07 ÷ 1.03)^(1/12) − 1 = 0.0031800. F × i + S = 3,975.04 + 2,000 = 5,975.04 and B × i + S = 318.00 + 2,000 = 2,318.00. n = ln(5,975.04 ÷ 2,318.00) ÷ ln(1.0031800) = 0.946885 ÷ 0.003175 = 298.2, so 299 months: 24.9 years, at age 54.9.

$60,000 a year, 4%, $2,000,000 invested, age 45. The FIRE number is $1,500,000, which you already have: 0 years, at age 45.

$12,000 a year, 4%, $100,000 invested, $2,000 a month, 2% return, 5% inflation, age 30. The real return is negative: i = (1.02 ÷ 1.05)^(1/12) − 1 = −0.0024127. FIRE number = $300,000. F × i + S = −723.81 + 2,000 = 1,276.19 and B × i + S = −241.27 + 2,000 = 1,758.73. n = ln(1,276.19 ÷ 1,758.73) ÷ ln(1 − 0.0024127) = −0.320735 ÷ −0.0024156 = 132.8, so 133 months: 11.1 years, at age 41.1. (If F × i + S were 0 or less, the balance would never reach the FIRE number.)

$50,000 a year, 4%, $0 invested, $100 a month, no growth, age 30. By age 100 you would have 840 × 100 = $84,000, far below $1,250,000, so the calculator shows "Not by age 100".

Other questions people ask

What is FIRE?

FIRE stands for "financial independence, retire early". The idea is to save and invest enough that your investments can pay for your spending, so work becomes optional, often well before a usual retirement age.

What is my FIRE number?

It is your yearly spending divided by your safe withdrawal rate. At 4%, that is 25 times your yearly spending: $50,000 a year needs $1,250,000. At 3.5% it is about 28.6 times.

Where does the 4% rule come from?

From studies of past US stock and bond returns (Bengen, 1994; Cooley, Hubbard and Walz, 1998). Taking 4% in the first year and then raising it with inflation lasted at least 30 years in most historical periods. Early retirees may need their money for 40 or 50 years, so many choose a lower rate to be cautious. It is a rule of thumb, not a guarantee.

Why does the calculator use a real return?

Your spending will rise with prices, so the calculator works in today’s money. It turns your expected return into a real return: (1 + return) ÷ (1 + inflation) − 1. A 7% return with 3% inflation is a 3.88% real return. Your savings are also in today’s money, so they rise with prices each year.

What speeds up reaching financial independence?

Two things matter most: how much you save and how much you spend. Spending less lowers the FIRE number and frees money to save, so it works twice. The return matters too, but you do not control it.

What does the calculator leave out?

Taxes, fees, Social Security, pensions, and changes in spending over time. Social Security can lower what your savings must pay later: if you were born in 1960 or later, your full retirement age is 67. It also uses one steady return; real markets go up and down.