Coast FIRE: Stop Saving and Let Compound Growth Do the Work
Coast FIRE means you've saved enough that compound growth alone will fund your retirement โ you can stop contributing and just let it grow. This frees you to take lower-paying but more fulfilling work, or reduce hours dramatically.
Ready to run the numbers?
Why: Coast FIRE is the most accessible FIRE variant โ you don't need to save aggressively forever. If you've invested enough by a certain age, compound growth handles the rest. This calculator tells you exactly when you can stop contributing.
How: We calculate the lump sum needed today that will grow to your retirement target (e.g., $1.5M at 65) using expected market returns. If your current portfolio exceeds this number, you've achieved Coast FIRE and can stop saving.
Run the calculator when you are ready.
Coast FIRE โ Stop Saving, Let Compound Interest Work
Calculate how much you need saved today to coast to retirement. No more contributions required โ your investments do the rest.
Age & Timeline
Savings & Spending
Returns & Assumptions
Coast Job Planning
Keep saving at $15,000/yr to reach Coast FIRE
Minimum income needed after coasting โ covers expenses only, no savings required
Portfolio Growth Projection
Coast FIRE Gap Analysis
Retirement Number Breakdown
๐ Calculation Breakdown
For educational and informational purposes only. Verify with a qualified professional.
๐ Key Takeaways
- โข Coast FIRE means you have enough saved to stop contributing โ your investments will grow to your retirement target by your target age.
- โข The Coast FIRE number = target retirement amount รท (1 + return rate)^years to retirement.
- โข The 4% rule (Trinity Study) suggests you need 25ร your annual spending in retirement.
- โข The earlier you start saving, the lower your Coast FIRE number โ compound interest does the heavy lifting.
Did you know Coast FIRE lets you work a lower-stress job?
How does Coast FIRE work?
Coast FIRE is a milestone in the Financial Independence, Retire Early (FIRE) movement. You reach Coast FIRE when your current investments have enough time to grow โ without any new contributions โ to your target retirement amount by your target age.
Step 1: Target Retirement Amount
Using the 4% rule: target = annual spending รท 0.04 = annual spending ร 25. For $50K/year spending, you need $1.25M.
Step 2: Inflation-Adjust
Multiply by (1 + inflation)^years to get the future value at retirement.
Step 3: Coast FIRE Number
Divide by (1 + nominal return)^years to get the present value โ what you need today.
๐ฏ Expert Tips
๐ก Start Early
Every year you delay costs you. A 25-year-old needs far less than a 35-year-old for the same retirement target.
๐ก Use Conservative Returns
Assume 5โ6% real returns for planning. Historical 7% is optimistic; sequence of returns can reduce outcomes.
๐ก Coast Job Flexibility
Once Coast FIRE, you only need income to cover expenses โ no savings required. Great for part-time or passion work.
๐ก Tax-Advantaged First
Max 401(k), IRA, HSA first. Tax-deferred growth accelerates your Coast FIRE timeline.
โ๏ธ FIRE Variants Comparison
| Type | Definition | Savings Required |
|---|---|---|
| Lean FIRE | Minimal retirement spending | Lowest |
| Coast FIRE | Stop saving now; coast to retirement | Moderate (this calc) |
| Regular FIRE | Full retirement now | 25ร annual spending |
| Fat FIRE | Luxury retirement | Highest |
โ Frequently Asked Questions
What is Coast FIRE?
Coast FIRE is a milestone where you have enough saved that, without adding another dollar, your investments will grow to your retirement target by your target age. You can "coast" โ work a lower-stress job that covers expenses while your nest egg grows.
How is Coast FIRE number calculated?
Coast FIRE Number = (Annual Spending / Safe Withdrawal Rate) ร (1 + inflation)^years รท (1 + nominal return)^years. Essentially: future target รท growth factor.
What is the 4% rule?
The Trinity Study found that withdrawing 4% of your portfolio in year one, then adjusting for inflation, had a 95%+ success rate over 30 years. So you need 25ร your annual spending (1 รท 0.04).
Can I retire early with Coast FIRE?
Coast FIRE is not full retirement โ it means you can stop saving for retirement. You still need income to cover current expenses until you reach full FIRE (25ร spending).
What return rate should I use?
Historical stock market returns are ~7% nominal. Use 5โ7% for planning; conservative planners use 5% for safety. Inflation is typically 2โ3%.
What if I am already Coast FIRE?
Congratulations! You can reduce work stress, take a lower-paying job you enjoy, or work part-time. Your investments will grow to your target without further contributions.
๐ Coast FIRE by the Numbers
๐ Sources
โ ๏ธ Disclaimer: This calculator provides estimates based on historical returns and the 4% rule. Past performance does not guarantee future results. Investment returns, inflation, and life circumstances vary. Consider consulting a financial advisor for personalized advice.
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