Coast FIRE Calculator

What Is Coast FIRE?

Coast FIRE is achieving enough retirement savings early that, without additional contributions, your investments will grow to fully fund retirement by traditional retirement age through compound growth.

Key Formula

Coast FIRE Number = (Annual Expenses × 25) / (1 + Real Return Rate)^Years Until Retirement

Where:

• Real Return Rate = (1 + Nominal Return) / (1 + Inflation Rate) - 1
• 25 = 4% safe withdrawal rate multiplier

How to Use

1. Enter Your Details:

   • Current age & target retirement age
   • Existing savings and expected annual expenses
   • Investment return and inflation assumptions

2. Interpret Results:

   • Chart shows growth trajectory vs. target
   • Summary displays your Coast FIRE number
   • Status indicates whether you’re on track

3. Adjust Parameters:

   • Experiment with different savings rates
   • Test various return assumptions
   • Modify retirement spending goals

FAQs

Q: How is Coast FIRE different from regular FIRE?
A: Coast FIRE means you stop contributing to retirement accounts, while regular FIRE means you can fully retire immediately.

Q: Why use 25× annual expenses?
A: Based on the 4% rule - withdrawing 4% annually from your portfolio gives 25 years of expenses.

Q: What’s a realistic return rate assumption?
A: Historically 7-8% for stock markets, but conservative estimates use 5-6% after inflation.

Terminology Explained

Coast FIRE Number:
The amount needed today that will grow to cover your full retirement.

Real Return Rate:
Investment return after accounting for inflation (nominal return minus inflation).

Safe Withdrawal Rate:
Percentage you can withdraw annually without depleting savings (typically 4%).

Compound Growth:
Earnings generating their own earnings over time - the engine behind Coast FIRE.

Financial Independence:
When your investments can cover living expenses indefinitely.