Coast FIRE Number

Personal Finance
Updated Apr 2026 • Has calculator

The portfolio balance today that will grow to your FIRE number by retirement without any further contributions.

What is Coast FIRE?

Coast FIRE is a milestone where your existing investment portfolio, left to grow without further contributions, will compound to your full FIRE number by your target retirement age. Once you reach your Coast FIRE number, you only need to cover current living expenses—you no longer need to save for retirement. The calculation discounts your FIRE target back to today's dollars using the expected real return of your portfolio.

Formula

Coast FIRE = FIRE Target ÷ (1 + Return)^Years to Retirement

Worked Example

Worked example — 35-year-old targeting retirement at 55 — 2024

2024

Step 1  FIRE target: $1,500,000 (retire at 55)
Step 2  Expected annual return: 7.0% (nominal)
Step 3  Years to retirement: 20 years
Step 4  Coast FIRE = $1,500,000 ÷ (1.07)^20 = $1,500,000 ÷ 3.870
Step 5  Coast FIRE number ≈ $387,630
Step 6  → With $387,630 invested today, no more retirement contributions needed

Source: Investopedia — Coast FIRE (2024-01-01)

Calculate Coast FIRE

Your full FIRE number — annual expenses ÷ withdrawal rate

Nominal annual portfolio return (7% is a common historical average)

How many years until you plan to retire

Coast FIRE Number

—

Not investment advice.

How to Interpret Coast FIRE

< 50000
Early stage — keep saving aggressively
50000 – 200000
Making progress — years of compounding ahead
200000 – 500000
On track — approaching or at Coast FIRE for many
> 500000
Achieved — compounding takes care of retirement

📚 FIRE Planning — Complete the path

  1. FIRE Number
  2. Safe Withdrawal Rate
  3. Coast FIRE
  4. CAGR
  5. Rule of 72
Sources
  1. Investopedia — Coast FIRE
  2. Damodaran, A. — Investment Valuation, 3rd ed.