Calculator Panel
Calculation Ready
Enter your values above and click Calculate.
What This Calculator Does
This calculator determines if your current savings are sufficient to grow to your ultimate retirement target via compounding alone, letting you stop ongoing savings and work only to cover active living expenses.
How to Use This Calculator
Enter current age, target retirement age, expected annual retirement expenses, current savings, safe withdrawal rate, and real return rate. Click Calculate to see your Coast FIRE number and status.
How the Calculation Works
The underlying math engine processes your inputs using exact formulas. This systematic approach ensures professional, institutional-grade calculation precision:
Mathematical Formula
Formula Legend:
- · Target Nest Egg = Required portfolio size at retirement (Annual Expenses / SWR).
- · Growth Rate = Expected real annualized return rate of investments (after inflation).
- · Years = Target Retirement Age minus Current Age.
Practical Example
Suppose you are 30 and want to retire at 60 (30 years to grow). Your target is a $1,500,000 nest egg, your current savings are $75,000, and you expect a 5.0% real return (adjusted for inflation):
Step-by-Step Mathematical Walkthrough:
- 1 Years to Grow = 60 - 30 = 30 years.
- 2 Expected compound growth factor = (1 + 0.05)^30 = 4.3219.
- 3 Coast FIRE Number = $1,500,000 / 4.3219 = $347,066.
- 4 You need $347,066 saved today to reach your target of $1,500,000 at age 60 without saving another dollar. Since you have $75,000 saved, your shortfall is $272,066.
Important Assumptions & Notes
- The investment return rate entered is 'real' (pre-deducted for inflation) to preserve today's purchasing power.
- You will cover 100% of your living expenses through active income until retirement.
- The portfolio remains invested in diversified assets.
Common Mistakes or Considerations
- Using a nominal return rate instead of an inflation-adjusted real rate, which results in underfunding your future lifestyle due to inflation.
- Stopping contributions before verifying your actual Coast FIRE threshold.
Frequently Asked Questions
What is Coast FIRE?
Coast FIRE is when you have saved enough early in life that you no longer need to contribute to retirement accounts. Compounding alone will carry you to your target, allowing you to take lower-paying, lower-stress jobs.
What is a safe real return rate to assume?
A conservative real return rate (adjusted for inflation) is 4% to 5% annually. The historical average real return of the S&P 500 is roughly 7.0%.
Can I stop saving completely once I hit Coast FIRE?
Yes, for retirement. However, you must still earn enough active income to cover your day-to-day living expenses until you reach retirement age.
How is Coast FIRE different from Barista FIRE?
Coast FIRE means your retirement is fully funded by compounding, and you work to cover active living expenses. Barista FIRE involves retiring from full-time work and working part-time to pay active bills and obtain healthcare.
How can I accelerate my path to Coast FIRE?
You can accelerate your path by front-loading your retirement accounts as early as possible in your career, maximizing the compound interest timeline.