Tiny Toolkit

Coast FIRE Calculator

Coast FIRE is the point at which you've invested enough that compound growth alone will carry you to full retirement — without ever adding another dollar. Enter your current savings, expected return, target retirement age, and FIRE number to see whether you've already hit Coast FIRE, and if not, how much more you need to invest and by when. Once you hit the Coast number, you only need to cover your current expenses — not save.

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Frequently Asked Questions

What is Coast FIRE?
Coast FIRE means you have saved enough that, even with zero additional contributions, your existing balance will grow to your full FIRE number by your target retirement age. You have "enough invested" and just need to let it compound.
How is the Coast FIRE number calculated?
Coast FIRE Number = FIRE Number / (1 + r)^years to retirement, where r is your expected annual return. This discounts your target nest egg back to today's dollars, showing how much you need invested now to reach it without adding more.
What return rate should I use?
A 7% annual return is a common assumption for a diversified stock portfolio after inflation. For a nominal (pre-inflation) return, 9–10% is often used. The actual return will vary; use a conservative estimate to avoid underestimating how much you need.
What do I do after reaching Coast FIRE?
Once you hit your Coast FIRE number, you no longer need to save aggressively for retirement. You can redirect contributions toward other goals — a home, travel, education — or simply work a lower-paying job you enjoy without worrying about retirement savings.

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