Coast FIRE Explained: Calculator + Complete Guide

TL;DR

Coast FIRE is the point where your savings will grow to your full retirement number on their own, even if you never invest another dollar. Once you hit Coast FIRE, you still need income for daily life, but you can stop stressing about retirement savings. For a 30-year-old targeting $1.2M at 65 with 7% returns, the Coast FIRE number is roughly $112,000.

What Is Coast FIRE?

Coast FIRE is a milestone on the path to financial independence. It's the moment when compound growth takes over. You've saved enough that your existing investments, left untouched, will reach your full FI number by your target retirement age.

The word "coast" is literal. You're coasting to the finish line. The engine is already running; you just need to keep your hands on the wheel for daily expenses.

How to Calculate Your Coast FIRE Number

The formula discounts your FI number back to the present using compound interest:

Coast FIRE Number = FI Number / (1 + expected return)^years until retirement

Example: You want $1,200,000 at age 65. You're 30. You expect 7% real returns. That's 35 years of compounding.

$1,200,000 / (1.07)^35 = $1,200,000 / 10.68 = $112,360

Once you have $112,360 invested at age 30, compound growth does the rest.

Why the FIRE Community Loves It

Coast FIRE reframes the conversation from "I need to save $1.2 million" to "I need to save $112,000 and then I'm free." That's a life-changing reframe. A few years of aggressive saving early can lock in Coast FIRE, giving decades of career flexibility.

The Variables That Matter

Target retirement age: Retiring at 65 vs 55 can cut your Coast number in half.

Expected return: Using 7% vs 6% changes your Coast number by 20-30%.

Your FI number: Reducing expenses by $10,000/year lowers your FI number by $250,000 and your Coast number proportionally.

Coast FIRE vs Barista FIRE

Coast FIRE means you keep working to cover current expenses; you just stop saving. Barista FIRE means you've downshifted to part-time work. Barista FIRE requires more savings because your part-time income might not fully cover expenses.

The Limits

Coast FIRE assumes consistent returns over decades. A prolonged downturn early in the "coasting" period could delay retirement. Think of it as a planning tool, not a guarantee.

Calculate Yours

Our Coast FIRE Calculator shows your Coast FIRE number at every age so you can see when the milestone approaches.

Find your Coast FIRE number →

See also: Barista FIRE Calculator | Years to FI Calculator

This article is for educational and informational purposes only. It does not constitute financial advice.