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Finance & money·Investment

Coast FIRE Calculator

Calculate your Coast FIRE number — how much to invest today so compound growth reaches your retirement target without further contributions.

Added Jun 16, 2026

Quick examples

Input

Result

Enter a value for annual expenses in retirement to see your result.

How it works

Coast FIRE is the point where your current investments will grow to your full FIRE number by retirement — without any additional contributions. Once you reach your Coast number, you only need to cover living expenses, not save for retirement.

Formula

Coast Number = FIRE Number ÷ (1 + r)^n

FIRE Number
Annual expenses ÷ withdrawal rate (e.g. $50k ÷ 4% = $1.25M)
r
Expected annual real return (as decimal)
n
Years until retirement (retirement age − current age)

Step by step

  1. 01Calculate your full FIRE number: annual expenses ÷ safe withdrawal rate.
  2. 02Determine years to retirement: retirement age − current age.
  3. 03Discount the FIRE number back to today using compound growth: FIRE Number ÷ (1 + r)^n.
  4. 04The result is your Coast FIRE number — how much you need invested today to retire without further contributions.
  5. 05If your current portfolio already exceeds your Coast number, you are already coasting.

Examples

$50k/yr expenses, $80k saved, age 30, retire at 65

To spend $50k/year in retirement at a 4% withdrawal rate, you need $1.25M. At 7% annual return over 35 years, you need only ~$117k invested today — it will grow to $1.25M by age 65 without further contributions.

Inputs

Annual expenses in retirement:
50000
Current investment portfolio:
80000
Current age:
30
Target retirement age:
65
Expected annual return:
7
Safe withdrawal rate:
4

Result

Your Coast FIRE number:
116861
Note: Coast FIRE uses nominal returns. For inflation-adjusted projections, use a real return (nominal return minus expected inflation, typically 2–3%). Once you hit your Coast number, you still need to earn enough to cover living expenses until retirement — the 'barista FIRE' variant covers this with part-time or lower-stress work. The 4% rule was based on a 30-year retirement. For early retirees targeting 40+ years, consider 3–3.5% withdrawal rate, which raises your FIRE number.

Related guides

  • How to Calculate Your Retirement Savings Goal

    Learn how to estimate the savings needed for retirement using the 4% rule, how to factor in inflation, Social Security or pension income, and how to close a.

  • What Is the FIRE Number?

    Everything you need to know about the FIRE number -- the 4% rule, how to calculate your target, FIRE variants (lean, fat, barista, coast), and what to include.

  • Personal Finance Guide: Budgeting to Investing

    A hub for personal finance: income after tax, budgeting rules, savings goals, debt payoff strategies, and long-term investing — with tools for each step.

  • What Is Coast FIRE? Financial Independence

    Invest enough today for your portfolio to reach your retirement target without future contributions. Explains the Coast FIRE formula, variants, and calculation.

Frequently asked questions

What is Coast FIRE?

Coast FIRE is the point where your invested savings will grow to your full FIRE number (retirement portfolio target) by your target retirement age — without any additional contributions. Once you hit your Coast number, you only need to earn enough to cover current living expenses.

How is Coast FIRE different from regular FIRE?

Regular FIRE means your portfolio is already large enough to retire now. Coast FIRE means your portfolio is large enough that, given time and compound growth, it will reach the regular FIRE number by retirement — but you haven't retired yet. Coast FIRErs typically work just enough to cover expenses, not save for retirement.

What return rate should I use?

The US stock market has returned roughly 10% nominal and 7% real (inflation-adjusted) over long periods. Using 7% (real) gives a conservative estimate. For a nominal projection, use 9–10% and remember the final portfolio will need to be discounted for inflation.

What if I've already passed my Coast FIRE number?

If your current portfolio exceeds your Coast FIRE number, you are already coasting. Your investments will grow to your full retirement target without any further contributions. You only need to cover your current living expenses until retirement.