- Enter your current and planned retirement ages.
- Set annual retirement spending and a withdrawal rate.
- Use an expected real return, which is return after inflation.
- Compare today’s required coast balance with your current investments.
Coast FIRE Calculator
Find the invested balance that could grow to your retirement target without additional contributions. This version separates the future spending target, the balance required today, and the surplus or shortfall against your current investments.
Planning assumptions
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years
$
$
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Result
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Amount needed today to coast
Retirement portfolio target—
Current balance—
Coast gap or surplus—
Growth multiple needed—
Retirement target = Annual spending ÷ Withdrawal rate
Coast balance today = Retirement target ÷ (1 + real return)years
What the result means
If your current investments are above the coast balance, they could theoretically reach the target without more deposits under the stated assumptions.
Coast FIRE is highly sensitive to return, retirement age, spending, and withdrawal assumptions. It is not a guarantee that contributions can safely stop.
A 32-year-old targeting $50,000 of annual spending at 65 with a 4% withdrawal rate needs $1.25 million at retirement. At a 5% real return, the coast balance today is about $250,000.
What does a Coast FIRE shortfall mean?
It is the additional amount that would need to be invested today for the current balance to compound to the retirement target without future deposits.
Why should Coast FIRE use a real return?
A real return keeps both the future spending target and investment growth in today’s purchasing power.
Can I still contribute after reaching the Coast FIRE balance?
Yes. Further contributions add a margin of safety, support an earlier retirement date, or allow higher future spending.
How does retiring later affect the coast number?
More compounding years generally reduce the balance required today, assuming the same target and return.
Does this calculator include Social Security?
Not directly. Reduce annual portfolio-funded spending by reliable expected benefits if you want to account for them.