Coast FIRE Calculator
Find when you can stop saving and let compound interest do the work.
Trinity Study default: 4%
S&P 500 historical avg: ~7% real
Your FIRE Number
$0
portfolio needed at retirement
Coast FIRE Number
$0
needed today to coast
Coast FIRE Status
Calculating...
Coast FIRE Age
--
with current contributions
Portfolio Growth Projection
Age Milestones
| Age | With Contributions | Coasting (no contributions) | Coast FIRE Target |
|---|
What is Coast FIRE?
Coast FIRE (Financial Independence, Retire Early) is a milestone where your current retirement savings, if left untouched, will grow to support your retirement by a target age without any additional contributions. Once you reach your Coast FIRE number, you only need to earn enough to cover current living expenses.
How Coast FIRE Differs from Regular FIRE
- Regular FIRE: Save aggressively until your portfolio can sustain your lifestyle through withdrawals (typically 25x annual spending)
- Coast FIRE: Save until compound interest alone will grow your portfolio to your FIRE number by retirement age
- Barista FIRE: Similar to Coast FIRE but you also withdraw a small amount, supplemented by part-time work
The Coast FIRE Formula
Coast FIRE Number = FIRE Number / (1 + real return rate) ^ (retirement age - current age)
Where FIRE Number = Annual Spending / Safe Withdrawal Rate
Key Assumptions
This calculator uses inflation-adjusted (real) returns, so the numbers are in today's dollars. The default 7% real return reflects the historical average of the S&P 500 after inflation. The 4% safe withdrawal rate is based on the Trinity Study, which found that a diversified portfolio historically survived 30-year withdrawal periods at this rate with high probability.