Coast FIRE Number
$0.00
Coast FIRE Calculator
See the portfolio you need today to coast to retirement using compound growth alone.
Financial Inputs
Enter inputs to see your Coast FIRE status.
Progress to Coast FIRE
0%
Projection Summary
Years to Retirement
0
Target Nest Egg
$0.00
Projected Wealth at Retirement
$0.00
The Ultimate Coast FIRE Calculator: Financial Independence on Your Terms
The traditional FIRE movement (Financial Independence, Retire Early) requires intense frugality and aggressive savings rates to build a multi-million-dollar portfolio as quickly as possible. For many people, grinding through extreme burnout just to quit their jobs in their 30s or 40s is unappealing and unsustainable.
Enter Coast FIRE. Coast FIRE is an alternative financial milestone that entirely removes the stress from retirement planning. Once you hit your Coast FIRE number, you have saved enough money early in life that compounding interest alone will carry your portfolio to your target retirement goal. You can completely stop contributing to your 401(k) or IRA. From that day forward, you only need to work enough to cover your current living expenses—giving you the freedom to downshift to a lower-stress job, start a passion business, or work part-time while your investments do the heavy lifting in the background.
The Coast FIRE Formula: Let Compound Interest Do the Work
To calculate your Coast FIRE number, you must reverse-engineer the power of compound interest. Instead of asking "What will my money grow into?", you are asking, "How much money do I need right now so that it naturally grows into my target retirement number?"
The Coast FIRE Equation
Coast Number = Target Nest Egg ÷ (1 + Rate of Return)Years to Retirement
Note: Always use an inflation-adjusted (real) rate of return so your future purchasing power is accurate in today's dollars.
The 3 Critical Variables:
- Time Horizon: This is your greatest asset. The younger you are, the smaller your Coast FIRE number is. A 25-year-old needs drastically less money to coast than a 45-year-old because their money has decades more time to double.
- Target Retirement Number: Using the 4% Rule, calculate your desired annual spending in retirement and multiply it by 25. (e.g., If you want to spend $60,000 a year, your target is $1,500,000).
- Expected Real Return: The stock market historically returns about 10% per year. However, inflation averages around 3%. Most financial planners use a conservative "Real Return" of 6% or 7% to account for inflation, meaning your final calculation is already adjusted for future price hikes.
Real-World Use Case: Escaping the Rat Race at 32
Let's look at a practical scenario. Sarah is a 32-year-old marketing manager who is burnt out. She wants to officially retire at 65. She calculates that she needs $1.2 Million to retire comfortably. Her current investment portfolio is sitting at $140,000. Assuming a 7% real annual return, can she quit her high-stress corporate job and take a fun, lower-paying job at a local bookstore?
- Step 1 (Time Horizon): 65 (Retire Age) - 32 (Current Age) = 33 Years to grow.
- Step 2 (The Math): $1,200,000 ÷ (1 + 0.07)33
- Step 3 (Calculate the Divisor): 1.0733 = 9.325
- Step 4 (Coast FIRE Number): $1,200,000 ÷ 9.325 = $128,686
The Result: Sarah only needs $128,686 invested today to hit her $1.2M goal by age 65. Because she already has $140,000, she has successfully reached Coast FIRE! She can stop investing for retirement entirely and take the lower-paying bookstore job with zero guilt.
The Variations of the FIRE Movement
"Financial Independence, Retire Early" is not a one-size-fits-all concept. As the movement has matured, different variations have emerged to fit different lifestyle goals and income levels.
| FIRE Type | The Goal | Lifestyle Implication |
|---|---|---|
| Fat FIRE | Retire early with a massive nest egg ($3M to $5M+). | Allows for a luxurious retirement, frequent travel, and no strict budgeting. Requires a very high income during working years. |
| Lean FIRE | Retire early with a minimal nest egg (under $1M). | Requires extreme frugality. You will live on $30k-$40k a year in retirement, meaning you must permanently keep expenses drastically low. |
| Barista FIRE | Save enough to mostly retire, but keep a part-time job. | You work 15-20 hours a week (e.g., as a barista) solely to get corporate health insurance and cover a tiny gap in your passive income. |
| Coast FIRE | Front-load your investments while young, then stop contributing. | You don't retire early. You just work jobs you genuinely enjoy to cover your immediate bills, knowing your retirement is already fully funded. |
Frequently Asked Questions
Does Coast FIRE account for inflation?
Yes, as long as you use an inflation-adjusted (real) rate of return in your calculation. The historical average stock market return is roughly 10%. If you assume an average inflation rate of 3%, you use a 7% expected return in the calculator. This means the final target number outputted by the calculator represents future buying power in today's dollars.
What if a bear market crashes my portfolio?
Coast FIRE relies on long-term time horizons (usually 10 to 30 years). Over any 20-year period in modern history, the stock market has always gone up, absorbing crashes like 2008 or 2020. However, because Sequence of Return Risk is real, many people aim to overshoot their Coast FIRE number by 10-15% just to build in a safety buffer.
Can I withdraw money once I hit Coast FIRE?
No. This is the most crucial rule of Coast FIRE. You can stop adding money to your accounts, but you cannot touch the principal or the growth. The entire mathematical formula relies on that money staying fully invested and untouched so it can compound until your designated retirement age.
What is the "4% Rule"?
The 4% rule (based on the famous Trinity Study) is a safe withdrawal rate for retirement. It suggests that if you withdraw 4% of your total portfolio value each year, your money should last for at least 30 years without running out. To easily find your target nest egg using this rule, take your desired annual spending and multiply it by 25.