How much do I need to never save again?

Coast FIRE is the point where compound growth alone carries you to your FIRE number by your target age. The math works in real (after-inflation) returns.

Current age

Target age (coast until)

Annual spending in retirement ($)

Safe withdrawal rate (%)

Nominal annual return (%)

Expected inflation (%)

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Coast number (today's money)

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FIRE number

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Real (after-inflation) return

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Growth factor until target age

What does Coast FIRE actually mean?

You stop contributing entirely. Your portfolio does the rest. The Coast number is the lump sum today that grows to your FIRE number by your target age — contributions after that point are optional, not required.

Why "Coast"?

Once you hit this number, saving is on cruise control: growth alone covers the remaining distance. Many people "coast" while still working (covering expenses from salary) and let the portfolio grow untouched.

The math

Coast = FIRE number ÷ (1 + real return)^years, where FIRE number = annual spending ÷ withdrawal rate, years = target age − current age, real return = (1+nominal)/(1+inflation) − 1. Example: $45k spending at 4% = $1.125M FIRE; at 30 with a 35-year runway and 3.88% real return → Coast ≈ $296k.