Coast FIRE Calculator

Calculate your Coast FIRE number: the amount to have invested today so it can grow to your retirement target without further contributions.

All amounts on this page are in today's money. Returns are converted to real (after-inflation) returns, so results are comparable to what things cost now.

Coast FIRE number today

$277,852

Not reached yet

You are $127,852 short of the number.

Coast FIRE at age 45 (in 15 years) if you keep contributing $12,000 a year.

FIRE number at retirement

$1,250,000

Real return used

4.39%

Balance at retirement if you stop contributing now (35 years)

$674,820

Portfolio balance vs. Coast FIRE line

In today's money. Once your balance is on or above the Coast FIRE line, growth alone is projected to reach your FIRE number by retirement.

Using your Coast FIRE number

The result is a planning estimate, not a forecast. It assumes a steady return, steady inflation and that you keep working to cover your living costs until retirement age. If you want to retire earlier than a traditional age, the FIRE calculator shows how long full financial independence could take. The retirement calculator projects savings over a working life, and the compound interest calculator lets you see how growth builds on itself. This is general information, not financial advice.

Related calculators and research

How It Works

  1. 1Enter your current age, planned retirement age and invested assets.
  2. 2Enter the annual spending you expect in retirement, in today's money, and a safe withdrawal rate.
  3. 3Set your expected nominal return and inflation, and add any pension or Social Security income.
  4. 4Optionally enter what you contribute each year until you reach Coast FIRE.
  5. 5Compare your assets with the Coast FIRE number and read the age at which you reach it.

The formula

  • Real return = (1 + Expected return) ÷ (1 + Inflation) − 1
  • FIRE number = (Annual spending − Pension income) ÷ Safe withdrawal rate
  • Coast FIRE number = FIRE number ÷ (1 + Real return)^Years to retirement

All amounts are in today's money. Growing the portfolio at the real return already removes inflation, so the FIRE number is not inflated separately.

Worked example

Age 30, retiring at 65, spending $50,000 a year in today's money, 4% withdrawal rate, 7% expected return, 2.5% inflation, $150,000 invested.

  1. 1Real return: 1.07 ÷ 1.025 − 1 = 4.39%
  2. 2FIRE number: $50,000 ÷ 0.04 = $1,250,000
  3. 3Coast FIRE number: $1,250,000 ÷ 1.0439^35 = $277,852
  4. 4Left alone, $150,000 grows to $674,820 by age 65, so Coast FIRE is not reached yet

You need $277,852 invested today. Adding $12,000 a year gets you to Coast FIRE in 15 years, at age 45.

A pension of $20,000 a year lowers the FIRE number to $750,000 and the Coast FIRE number to $166,711.

Frequently Asked Questions

What is Coast FIRE?

Coast FIRE means you have already invested enough that, with no further contributions, growth alone should carry your portfolio to your retirement number by your chosen retirement age. You still need to earn enough to cover your living costs until then.

How is the Coast FIRE number calculated?

First, the FIRE number is annual spending (minus any pension income) divided by the withdrawal rate. The Coast FIRE number is that amount discounted back to today at the real return: FIRE number ÷ (1 + real return) to the power of years until retirement.

Why does inflation matter, and what is the real return?

Prices rise over time, so a future dollar buys less than one today. The real return is (1 + nominal return) ÷ (1 + inflation) − 1. This calculator works in today's money, so a 7% nominal return with 2.5% inflation is about 4.39% real. Ignoring inflation makes the number you need look smaller than it is.

How does Coast FIRE differ from Barista, Lean and Fat FIRE?

Coast FIRE is about when you can stop saving while you keep working. Barista FIRE means leaving full-time work and covering part of your spending with part-time income. Lean FIRE and Fat FIRE describe the spending level you retire on: a modest budget versus a generous one. They can be combined, for example a Lean Coast FIRE target.

How does a pension or Social Security change the number?

Guaranteed income reduces how much your portfolio has to provide. The calculator subtracts it from your annual spending before dividing by the withdrawal rate, which lowers both the FIRE number and the Coast FIRE number. Enter the amount in today's money, and check how your pension is taxed and indexed.

What return assumption is reasonable?

There is no guaranteed figure. Long-run historical returns for diversified stock portfolios have often been quoted in the mid to high single digits before inflation, but past returns are not a promise of future results and can be far lower for long periods. Test a cautious case as well. This tool is for education and is not financial advice.