Coast FIRE: The Number That Lets You Stop Saving

In short: Coast FIRE is the moment your invested pot is big enough that, with no further contributions, compounding alone will carry it to a full retirement fund by your target age. You still work — but only to cover current living costs, not to save. Find the number with the Coast FIRE calculator. The catch most tools hide: the target must be in today's buying power, or inflation flatters it.

How Coast FIRE Works

Full financial independence means having the whole pot now. Coast FIRE is one step back: you front-load your saving early, then let time do the rest. Because compounding is strongest over long horizons, money invested in your 20s and early 30s can double several times before retirement without a single extra contribution.

Save hard early, hit your Coast number, and your future retirement is already funded — you just have to not touch it.

A Worked Example

Suppose you'll need a $1 Million pot at 60 (in today's money). At a ~5% real return, the amount you need invested today shrinks the younger you are:

See the doublings for yourself with the compound interest calculator, then pin your exact figure with the Coast FIRE calculator.

Why It Matters

Coast FIRE buys freedom before full retirement. Once you hit it, you can drop to a lower-paid but more enjoyable job, take a career break, or stop stressing about saving rate — because the retirement math is already solved. It reframes the goal from a distant finish line into a milestone you can hit in your 30s or 40s.

Common Mistakes

Using the inflated future number.

A pot that looks enormous in future dollars may be ordinary once deflated to today's buying power. Always set the target in real terms — that's the difference between a plan and a mirage.

Assuming an unrealistic return.

Coast FIRE is sensitive to the return you assume. Use a conservative real return, and remember a bad early decade (sequence risk) can knock the plan off course. Pressure-test your full number with the FIRE calculator.

Your Next Decision

Find your Coast number today. If you're past it, you've earned the option to ease off. If you're not, the gap tells you exactly how much more to invest before compounding can take over — and the savings rate calculator shows how fast you'll close it.