compare_arrowsStrategy Comparison

Coast FIRE vs Regular FIRE: Is Coasting Right for You?

Reference FIRE Number

$1.5M

Target Age

Monthly Needed

$1K

Coast FIRE is one of the most liberating concepts in the FIRE community: once your invested portfolio is large enough to grow to your FIRE number by retirement age without any additional contributions, you've "reached the coast." You can stop contributing, maintain just enough income to cover current expenses, and let compound interest carry you to retirement. For a 30-year-old with $100,000 invested targeting $1.5M by 65, the Coast FIRE number at 7% real return is about $160,000 — achievable in 2–3 more years of saving.

The Coast FIRE calculation: Present Value = Future FIRE Number / (1 + real return)^years. At 7% real return, $1.5M needed at 65 from age 30 (35 years): Coast number = $1,500,000 / (1.07)^35 = $1,500,000 / 10.68 = $140,500. Once you have $140,500 invested and stop contributing entirely, it will grow to $1.5M by 65 at 7% average annual returns.

Regular FIRE — saving aggressively until you have your full FIRE number — requires maintaining high savings rates through your working life. Coast FIRE allows switching to a less demanding income once the coast threshold is reached, giving you flexibility to pursue lower-paying but more meaningful work, take parental leave without stress, or work part-time years earlier than full FIRE would allow.

The key risk of Coast FIRE: your investment growth rate is uncertain. At 5% real return instead of 7%, that $140,500 grows to only $772,000 by 65 — well short of $1.5M. Coast FIRE requires trusting long-run market returns and typically assumes Social Security income as a backup. Most Coast FIRE planners build in a 10–20% safety margin above the calculated coast number before actually stopping contributions.

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Common Questions

What is Coast FIRE?expand_more

Coast FIRE is when your current investment portfolio is large enough that, with no additional contributions, it will grow to your FIRE number by your target retirement age using expected investment returns. Once you reach your coast number, you only need to earn enough to cover current living expenses — no further investing required.

How do you calculate your Coast FIRE number?expand_more

Coast Number = FIRE Number / (1 + real return)^years until retirement. Example: $1.5M FIRE number, 30 years to retirement, 7% real return: $1,500,000 / (1.07)^30 = $1,500,000 / 7.61 = $197,000. Once you have $197,000 invested, you've coasted — no more contributions needed. Use the calculator above to find your personalized coast number.

Is Coast FIRE better than regular FIRE?expand_more

Neither is better — they serve different goals. Regular FIRE achieves full financial independence (no need to work). Coast FIRE gives you flexibility decades earlier but still requires some income until traditional retirement age. Coast FIRE is particularly valuable for those who want to reduce work stress, switch to more meaningful but lower-paying work, or take extended breaks from full-time employment.

What if market returns are lower than expected in a Coast FIRE plan?expand_more

This is the primary risk. Build a safety margin: aim for 110–120% of your calculated coast number before actually stopping contributions. Continue some investing even after reaching the coast threshold when income allows. Have a fallback plan to resume contributions if you're 15+ years from retirement and markets significantly underperform your assumptions.

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