What is Coast FIRE? A plain-English definition with a real example

TL;DR: Coast FIRE is the point where your current invested savings, left alone with zero further contributions, will compound to your full FIRE number by a normal retirement age purely on investment growth. Once you hit it, continuing to contribute is optional acceleration, not a requirement to eventually reach financial independence.

The concept in one sentence

If you stopped investing today — literally zero more contributions, ever — would your current savings still grow, on their own, into enough money to retire on by age 60 (or whatever retirement age you're targeting)? If yes, you've hit Coast FIRE. You can "coast" the rest of the way on growth alone, or keep contributing to reach full financial independence earlier than that traditional retirement age.

A worked example

Someone who needs a ₹1.5 crore FIRE number by age 60, currently age 30, with a 12% expected return and 6% inflation, needs roughly ₹28-29 lakh invested today to coast the remaining 30 years to that target on growth alone (the exact figure depends on discounting the target for both inflation and return — see the calculation method below). If they currently have exactly that amount invested, further contributions become optional; every rupee (or dollar) contributed beyond that point is purely for reaching independence sooner than 60, not a requirement to get there eventually.

Why this changes how people think about savings rate

Coast FIRE reframes "I need to save aggressively forever" into "I need to save aggressively until I hit this specific number, then I have a real choice." For many people in their 30s with a decade or more of consistent saving behind them, they're closer to this point than they realize — and knowing the actual number, rather than a vague feeling, changes decisions like whether to take a lower-paying but more fulfilling job, or reduce work hours.

The calculation, correctly done

The naive version just discounts your FIRE number by your investment return alone — but your FIRE number is really a target for FUTURE, inflated expenses, not today's expenses. A methodologically correct Coast FIRE number discounts by the difference between your investment return and inflation (the "real" return), not the nominal return alone — skipping this step meaningfully understates how much you actually need invested today.

Calculate your own Coast FIRE number

Our Retirement & FIRE Readiness Report calculates this correctly — discounted by your real return, not just nominal — alongside your lean/standard/fat FIRE numbers and years-to-FIRE timeline.

Frequently asked questions