Coast FIRE Explained: How Much You Need Before You Can Stop Saving

A 30-year-old with roughly $180,000 invested today could stop contributing entirely and still reach a $1.25 million target by 65 at a 7% average annual return.

Direct answer: Coast FIRE is the invested amount that, left untouched, compounds to your full FIRE number by a target age — calculated by discounting your FIRE number backward at an assumed return rate.

Coast FIRE is a milestone within the broader FIRE (Financial Independence, Retire Early) framework. Once an investor's portfolio reaches their Coast number, continued contributions become optional — existing investments, given enough years and an assumed rate of return, will compound to the full target without further input.

The calculation works backward from a standard FIRE number using the compound growth formula: divide the target FIRE number by (1 + expected return) raised to the number of years remaining until the target retirement age. A larger number of remaining years lowers the required Coast number substantially, which is why the concept resonates most with younger investors.

Reaching Coast FIRE does not mean stopping work — many who hit the milestone continue working, but can shift to lower-paying, more meaningful, or shorter-hour roles since income is no longer required to fund the retirement portfolio, only current living expenses.

The Coast FIRE concept pairs naturally with a true-hourly-wage view of work: once the investment portfolio is 'coasting,' every additional hour worked is effectively funding only current lifestyle, not long-term retirement, which changes how many people evaluate raises, promotions, or career changes.

Frequently Asked Questions

What is the difference between Coast FIRE and full FIRE?

Full FIRE means a portfolio is large enough to fund all living expenses immediately; Coast FIRE means a smaller portfolio will grow into that full number over time without further contributions.

Does reaching Coast FIRE mean I should stop working?

Not necessarily — many people who reach Coast FIRE continue working, but often shift toward lower-stress, part-time, or more meaningful roles since income no longer needs to fund retirement savings.

Want to see your own numbers? Try the free Life-Hours Calculator.