Calculate your FIRE number and discover how much you need to save today to reach financial independence
$
Enter your total retirement savings goal in dollars (e.g., $1,000,000)
%
Enter your expected annual investment return as a percentage (e.g., 7% for balanced portfolio)
years
Enter the number of years until your target retirement date
Amount Needed Today (Coast FIRE Number)—
Growth from Today to Retirement—
Monthly Savings Equivalent (if saving today)—
What does this mean? The Coast FIRE Number shows the lump sum you need to invest today to reach your retirement goal without adding any additional contributions. The growth amount displays how much your initial investment will earn over time. The monthly equivalent helps you understand what this single investment represents compared to ongoing monthly savings.
Understanding Coast FIRE
Coast FIRE is a financial strategy where you save aggressively for a number of years, then stop contributing entirely and let your investments grow until retirement. This approach allows you to "coast" into your retirement goal without additional effort, providing flexibility in your career or personal life during later years.
How the Coast FIRE Calculator Works
The calculator determines the exact lump sum amount you need to invest today so that compound interest alone will grow it to your target retirement number. By entering your desired retirement amount, expected investment returns, and years until retirement, the tool performs the mathematical calculations instantly. This inverse calculation shows you what single investment today replaces years of monthly contributions.
The Power of Compound Interest
Compound interest is the engine behind Coast FIRE. When you invest a sum today, it doesn't just sit idle—it generates returns, and those returns generate their own returns. Over 20-30 years, this exponential growth can transform a modest initial investment into a substantial retirement nest egg. For example, $300,000 invested at 7% annual returns grows to approximately $1,150,000 in 25 years. The Coast FIRE Calculator reveals exactly how much you need today to harness this powerful effect.
Using Your Results
Once you have your Coast FIRE number, you have several options. You can invest that amount immediately and stop all contributions, providing complete career flexibility afterward. Alternatively, you can continue saving beyond this amount to accelerate your timeline or build additional security. The monthly savings equivalent shows what consistent monthly contributions would equal your lump sum investment, helping you evaluate whether a one-time investment or ongoing contributions better suits your financial situation.
Choosing Your Expected Return Rate
The expected annual return significantly impacts your results. Conservative investments like bonds might return 4-5% annually, while diversified stock portfolios historically average 7-10%. Your return assumption should align with your risk tolerance and chosen investment strategy. Using 7% represents a balanced, historically-grounded estimate for a mixed portfolio of stocks and bonds.
Practical Applications and Planning
Coast FIRE works best for individuals who can access a substantial lump sum through inheritance, bonus, or aggressive early savings. This strategy is particularly valuable for those in their 30s or 40s who have accumulated significant savings and want to reduce work intensity while still reaching retirement goals. Use this calculator annually to reassess your targets as your actual investment returns accumulate and your timeline adjusts.
What is Coast FIRE and how is it different from regular FIRE?
Coast FIRE is a variation of the FIRE (Financial Independence, Retire Early) movement where you save aggressively until reaching a specific number, then stop contributing and let compound interest do the work. Regular FIRE typically involves consistent contributions throughout your career. Coast FIRE offers flexibility because once you reach your coast number, you can reduce work hours, change careers, or pursue other goals without affecting your retirement timeline.
How realistic is achieving a 7% annual return?
A 7% annual return is historically realistic for a balanced portfolio of approximately 60% stocks and 40% bonds. However, returns vary yearly—some years you'll earn more, others less. It's important to use a return rate that matches your investment strategy and risk tolerance. More conservative portfolios might target 5%, while aggressive portfolios might assume 8-9%.
Can I adjust my Coast FIRE plan after investing the initial amount?
Absolutely. Coast FIRE is flexible. If you continue earning income after reaching your coast number, you can choose to save additional amounts to accelerate your retirement or increase your retirement spending. You can also recalculate periodically using the actual returns your investments earned to ensure you're on track.
What if I don't have access to a lump sum today?
Coast FIRE specifically requires an upfront investment. If you don't have a lump sum available, traditional FIRE with monthly contributions may be more suitable. However, you can use this calculator to set a savings goal—determine how much you'd need to save monthly to accumulate your coast number, then begin regular investing.
How should I invest my Coast FIRE amount?
Your investment strategy should match your risk tolerance and years to retirement. With 20+ years, a growth-oriented portfolio (stocks and bonds) is typically appropriate. With less time, consider more conservative allocations. Consider low-cost index funds, target-date funds, or diversified ETFs. Consult a financial advisor for personalized recommendations based on your circumstances.