Coast FIRE Calculator
Find the amount you need invested today so you can stop saving for retirement and let compounding do the rest. Results update as you type.
Your Coast FIRE number by age
The earlier you hit your number, the less you need, compounding has more time to work. Based on your inputs above:
| If you're this age… | You need invested today | Years to grow |
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What is Coast FIRE?
Coast FIRE is the point where you have enough invested that, without adding another penny, your portfolio will grow to your full retirement number by the time you retire. Once you reach it, you still cover your day-to-day expenses, but you no longer need to save for retirement. You can "coast": take a lower-paying job you enjoy, go part-time, or start a business, knowing retirement is already handled.
Your FIRE number is the portfolio that lets you live off withdrawals indefinitely, usually your annual spending divided by a safe withdrawal rate (the 4% rule = spending × 25). Your Coast FIRE number is that target discounted back to today using compound growth. Read the full guide →
How this calculator works
Everything is shown in today's money. We take your expected investment return and subtract inflation and fees to get a real growth rate, then:
FIRE number = annual spending ÷ withdrawal rate
Coast FIRE number = FIRE number ÷ (1 + real return)years to retirement
The chart projects your current investments plus any monthly contributions forward at your real return, so you can see exactly when your net worth crosses the FIRE target.
Frequently asked questions
How do I know if I've reached Coast FIRE?
Enter your current investments and set your monthly contribution to 0. If your projected net worth at retirement still reaches your FIRE target, you've hit Coast FIRE, the status box turns green.
What return rate should I use?
A common conservative assumption is 7% nominal (roughly 4–5% after 2–3% inflation). The US market has historically returned ~10% before inflation, but planning with a lower number builds a safety margin. Adjust it under "Advanced assumptions."
Does this account for inflation?
Yes, we subtract your inflation rate from your investment return, so every figure is in today's dollars. You don't need to guess future cost-of-living increases.
Can I still contribute after reaching Coast FIRE?
Absolutely, you'll reach full FIRE earlier and retire with a larger cushion. Coast FIRE just means you no longer have to save.
Is the 4% rule safe?
The 4% safe withdrawal rate comes from the Trinity Study and held up over 30-year historical periods. Some people use 3.5% for extra caution, adjust it in the advanced settings.