Coast FIRE: The Complete Guide
Coast FIRE is the point where your existing investments will grow to your FIRE number by traditional retirement age with no further contributions — you only need to earn enough to cover living expenses until then.
What is Coast FIRE?
Coast FIRE is the point in your FIRE journey where you have saved enough money that — if you never contribute another dollar — your existing investments will still grow to your full FIRE number by traditional retirement age (usually 65).
The name comes from the idea that you can 'coast' toward retirement. You no longer need to save aggressively. You just need to earn enough to cover your current living expenses while your investments do the heavy lifting through compound growth.
For example, if your FIRE number is $1,000,000 and you're 35 years old, your Coast FIRE number might be around $200,000. Once you have $200,000 invested, it will grow to over $1,000,000 by age 65 at a 7% return — with zero additional contributions.
How to Calculate Your Coast FIRE Number
The Coast FIRE formula uses the future value of a lump sum:
Coast FIRE Number = FIRE Number ÷ (1 + r)^n
Where: - FIRE Number = your target portfolio (annual expenses × 25) - r = expected annual return (typically 7%, or 5% after inflation) - n = years until traditional retirement age
Example: Your FIRE number is $1,000,000, you're 35, you plan to 'coast' until 65 (30 years), and you expect a 7% return:
Coast FIRE Number = $1,000,000 ÷ (1.07)^30 = $1,000,000 ÷ 7.61 ≈ $131,400
So once you have about $131,000 invested, you could theoretically stop saving entirely and still reach your FIRE number by 65. Use our Coast FIRE Calculator to run your own numbers instantly.
Coast FIRE vs Barista FIRE vs Full FIRE
These three strategies sit on a spectrum of how much you keep working and saving:
Coast FIRE — You stop contributing to your investments but still work to cover living expenses. Your existing savings grow untouched.
Barista FIRE — A subset of Coast FIRE where you switch to part-time work (often for health insurance). You may still contribute small amounts.
Full FIRE — You stop working entirely and live off portfolio withdrawals.
The key difference is whether you're still touching your investments. Coast FIRE means leaving your nest egg completely alone to compound; Barista FIRE means part-time income covers expenses (and sometimes adds small contributions); Full FIRE means withdrawing from the portfolio.
The Risks of Coasting
Coasting isn't without risk. The main dangers:
1. Lower-than-expected returns — If the market returns 4% instead of 7%, your portfolio will fall far short. A 30-year coasting plan is highly sensitive to the actual return you earn.
2. Inflation — Your FIRE number is based on today's dollars, but your future expenses will be higher. Use inflation-adjusted returns (5% real) for a more conservative estimate.
3. Lifestyle creep — If you 'coast' into a lower-paying but more expensive lifestyle, you may struggle to cover expenses without dipping into investments.
4. Sequence of returns risk — Bad early returns while coasting have an outsized impact because you're not adding new money to buy the dip.
Coast FIRE works best as a milestone and a mindset shift — not a hard guarantee. Many people use it as permission to downshift their career while still contributing when possible.
Is Coast FIRE Right for You?
Coast FIRE is ideal if:
- You've already saved 20-40% of your FIRE number and want to reduce stress. - You'd like to switch to a lower-paying but more fulfilling career. - You want to work part-time for health insurance or social connection.
It's less suitable if you're far from your Coast FIRE number, if you're in a low-paying field with little flexibility, or if you genuinely want to retire fully as soon as possible.
Use our Coast FIRE Calculator to find your Coast FIRE number, then check our Compound Interest Calculator to see exactly how your current savings will grow without any additional contributions.
Frequently Asked Questions
What is the Coast FIRE formula?
Coast FIRE Number = FIRE Number ÷ (1 + r)^n, where r is your expected annual return and n is the number of years until traditional retirement age. For example, a $1,000,000 FIRE number 30 years away at a 7% return requires about $131,000 saved today.
How much money do I need for Coast FIRE?
It depends on your FIRE number and time horizon. As a rough guide, if you're 25-30 years from retirement, your Coast FIRE number is roughly 15-20% of your full FIRE number. If you're only 10-15 years away, it's 50-60%. Our Coast FIRE Calculator gives you the exact number.
Is Coast FIRE risky?
Yes — it relies on future market returns materializing as expected. If returns come in lower than your assumption, or if inflation is higher than expected, your portfolio may fall short. Use a conservative return assumption (5-6% nominal) to build in a safety margin.
What's the difference between Coast FIRE and Barista FIRE?
Coast FIRE means you've saved enough that your investments will reach your FIRE number without more contributions; you just work to cover expenses. Barista FIRE is a version of this where you specifically switch to part-time work, often to keep health insurance benefits.