InvestmentCalculators

Coast FIRE Calculator

Find the portfolio size today that, left to compound on its own, will fund your full retirement — no more contributions required.

Your plan

32 yrs
65 yrs
$
$
4.0%
7.0%
Coast FIRE target
$160,852
9.33× multiplier
Status
Not yet
Save $10,852 more
Projected at retirement
$1,398,801
vs $1,500,000 FIRE target

Projection vs. target

How this calculator works

The Coast FIRE number is your full FIRE target divided by the growth multiplier from today until retirement age: CoastFIRE = FIRE / (1 + r)^n.

For example, if your FIRE number is $1,500,000, you're 35, your target retirement age is 65 (30 years of growth), and you expect 7% real returns, your Coast FIRE number is $1,500,000 / 1.07^30 ≈ $197,000. Accumulate that much and your portfolio will grow to the FIRE number by 65 on its own.

The calculator compares your current savings against the Coast FIRE target and tells you whether you've crossed the threshold.

Coast FIRE explained

Coast FIRE is a milestone on the path to full financial independence. Reaching Coast FIRE means you've saved enough that your existing portfolio, compounding untouched, will grow to your full FIRE number by your target retirement age. You're no longer required to save for retirement — future contributions only accelerate the timeline.

Coast FIRE is psychologically significant. Reaching it changes the calculus of work, career, and lifestyle. You might reduce hours, pivot to a lower-paying but more fulfilling role, take a sabbatical, or start a side project without financial pressure. You still need to cover current living expenses, but the retirement clock has stopped.

Coast FIRE is related to, but distinct from, Barista FIRE. Barista FIRE means your portfolio covers most retirement needs, but you supplement with part-time income (classically, a part-time retail job with health insurance benefits — hence 'barista'). Coast FIRE more rigorously means you've saved enough that you don't need to save again for retirement, though current living expenses still need coverage.

The best time to hit Coast FIRE is in your 30s or early 40s. Because it relies on decades of compounding, the math strongly rewards younger savers. A 25-year-old needs a much smaller Coast FIRE number than a 45-year-old targeting the same retirement age — sometimes 3-4x less. This is the clearest case for front-loading savings early in a career.

Frequently Asked Questions

Am I still saving for retirement after Coast FIRE?
Mathematically, no — your existing balance will compound to your full FIRE number on its own. Practically, most Coast FIRE adherents continue contributing at a reduced rate as a margin of safety against sequence-of-returns risk, or they redirect savings toward Coast FIRE's variants (short-term goals, entrepreneurship, lifestyle).
What return assumption should I use?
Because Coast FIRE relies entirely on compounding over decades, conservative return assumptions are critical. Most Coast FIRE analysts use 5-7% real (inflation-adjusted) returns rather than 7-10% nominal. This provides margin for sequence-of-returns risk and periods of below-average market performance.
What if the market drops after I hit Coast FIRE?
You're not fully insulated. If markets decline significantly in your first post-Coast years, your portfolio might no longer compound to your FIRE target by retirement age. This is why Coast FIRE conservatism matters — targeting higher confidence (lower return assumptions, slightly larger buffer) protects against this risk.
Is there Coast FI for a non-traditional retirement age?
Yes — you can target any retirement age. Shorter horizons (retiring at 50 instead of 65) require larger Coast FIRE numbers because there's less time to compound. The calculator's retirement-age input lets you model different target ages.
How does Coast FIRE interact with Social Security?
Social Security reduces the portfolio size you need at traditional retirement age. If you plan to claim Social Security at 67 and it will cover 30% of expenses, your portfolio only needs to cover 70% — reducing both your FIRE and Coast FIRE numbers proportionally.

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