Coast FIRE Calculator

What Coast FIRE actually is

Coast FIRE is the least extreme member of the FIRE (Financial Independence, Retire Early) family, and arguably the most practical. The idea: at some point, the money you've already invested will grow into your full retirement number without another dollar of contributions — compounding does the rest of the work. Once your balance crosses that line, retirement is funded. Working is still necessary, but only to pay for today; every optional dollar becomes truly optional.

That changes decisions long before retirement. Past your coast number, you can take the lower-paying job you'd enjoy more, work fewer hours, absorb a career break — without touching the retirement math.

How the coast number is computed

Three steps. First, your retirement target in today's dollars: annual spending ÷ withdrawal rate (at 4%, that's 25× spending). Second, inflate it to retirement-year dollars, because prices won't stand still. Third, discount that back to today at your expected return — the result is the balance that, left alone, compounds into the target right on schedule.

The coast age — the number this page adds

Most coast calculators stop at "here's your number." The more useful question is when you'll cross it: keep saving at your current pace and your balance rises while the coast line rises to meet you — where they intersect is your coast age. From that year to retirement, saving is a choice, not a requirement. Try moving the monthly savings input and watch the crossing slide.

Is Coast FIRE the same as retiring early?

No — and the difference is the point. FIRE splits into flavors, and Coast is the one where nothing outwardly changes.

Regular FIRE is the baseline: save roughly 25 times annual spending and paid work becomes optional. Lean FIRE reaches that sooner by shrinking the spending side — freedom bought with frugality, and little slack for surprises. Fat FIRE goes the other way: a much larger pile, no pinching, usually a high income and a longer runway. Barista FIRE is a halfway exit — leave the demanding career, keep light or part-time work so the portfolio only has to cover the gap.

Coast FIRE is a different kind of milestone. It's the day your existing investments, left completely alone, would compound into your retirement number by retirement age without another dollar saved. Past it, saving more buys an earlier retirement or extra cushion — but it's no longer required for the baseline plan to work. You keep working; the job still pays the bills. What changes is the pressure. A lower-paying job you like, a sabbatical, one parent staying home — those become affordable without endangering the destination, because the destination is already funded.

The catches are worth naming. The coast claim assumes a steady return, and a bad decade moves your coast age. It assumes you genuinely stop at the same retirement age — coasting to 65 is much cheaper than coasting to 50. And it's access-blind: your total can be on track while too much of it sits locked in retirement accounts, which matters for any early version of the plan. The coast number says the pile is big enough; it says nothing about whether you can reach it when you want to.

None of the flavors is correct. They're points on a spectrum between how much you save, how you want to live, and how completely you want to stop working. The number this page computes is the entry ticket to that conversation, not the end of it.

Common questions