Coast FIRE Calculator
Calculate whether your current retirement savings can grow to support your retirement without any additional contributions. Find out if you have already reached Coast FIRE or how close you are.
What Is Coast FIRE?
Coast FIRE is a financial milestone where you have saved enough in your retirement accounts that, even without making another contribution, your investments will grow through compound returns to support your desired retirement lifestyle by the time you reach your target retirement age. Once you hit this number, time and compound growth do the remaining work for you.
The concept gets its name from the idea that you can "coast" to retirement. You still need to earn enough to cover your current living expenses, but you no longer need to actively save for retirement. This can be a liberating milestone because it opens up flexibility in your career. You might choose to work a lower-paying job you enjoy more, reduce your hours, take a sabbatical, or pursue a passion project without worrying about whether you are falling behind on retirement savings.
The Coast FIRE number depends on three variables: how much you plan to spend in retirement, your assumed safe withdrawal rate, and the expected rate of return on your investments between now and retirement. The formula works backward from your target nest egg, discounting it to present value based on expected growth. If your current savings exceed that present value, you have reached Coast FIRE.
Coast FIRE Number = (Annual Spending / SWR) / (1 + Return)^Years
Your savings today must equal or exceed this number to coast to retirement
Coast FIRE vs Other FIRE Variations
The FIRE (Financial Independence, Retire Early) movement encompasses several different strategies, each with a different level of savings and lifestyle expectation. Understanding where Coast FIRE fits helps you choose the approach that aligns with your goals.
| FIRE Type | Target | Description |
|---|---|---|
| Lean FIRE | 25x minimal expenses | Retire early on a lean budget, typically under $40,000 per year. Requires significant lifestyle sacrifices but is achievable on a modest income. |
| Regular FIRE | 25x current expenses | Retire early while maintaining your current standard of living. The classic FIRE target based on the 4% safe withdrawal rate. |
| Fat FIRE | 25x comfortable expenses | Retire early with a generous budget, typically over $100,000 per year. Allows for travel, hobbies, and a comfortable lifestyle without financial constraints. |
| Coast FIRE | Present value of nest egg | Save enough early so compound growth handles the rest. You still work to cover current expenses but stop retirement contributions. |
| Barista FIRE | Partial savings + part-time work | Similar to Coast FIRE but includes part-time work for health insurance and some income. Named after part-time barista jobs that offer benefits. |
Coast FIRE is often the first FIRE milestone people reach because it requires less total savings than full financial independence. It serves as an important psychological checkpoint that confirms your retirement is on track, even if full early retirement is still years away.
The Power of Starting Early
Coast FIRE illustrates one of the most powerful concepts in personal finance: the earlier you invest, the less total money you need to save. Compound growth is exponential, meaning each additional year of growth makes a significant difference in your final portfolio value.
Consider two investors who both want $1,250,000 by age 65 (enough to withdraw $50,000 per year at a 4% rate). Assuming a 7% annual return:
Starting at Age 25
- Coast FIRE number: ~$83,800
- 40 years of compound growth
- Money multiplies roughly 15x
- Achievable in a few years of saving
Starting at Age 40
- Coast FIRE number: ~$337,000
- 25 years of compound growth
- Money multiplies roughly 3.7x
- Requires many more years of saving
The difference is striking. Starting 15 years earlier reduces the required Coast FIRE number by roughly 75%. This is why financial advisors consistently emphasize the importance of beginning to invest as early as possible, even if the amounts are small. Every year of delay requires meaningfully more savings to reach the same destination.
Even if you cannot save aggressively in your twenties, small consistent contributions during those early years carry an outsized impact on your long-term wealth. A few thousand dollars invested at age 22 can be worth more at retirement than tens of thousands invested at age 45.
What to Do After Reaching Coast FIRE
Reaching Coast FIRE is a significant achievement, but it does not mean you should stop planning or making intentional financial decisions. Here are several strategies to consider once you have crossed this threshold.
Reassess Your Career
With retirement savings no longer a pressing concern, you have the freedom to evaluate your career based on fulfillment rather than salary alone. Some people use this flexibility to transition into lower-stress roles, start a business, pursue creative work, or shift to part-time employment. The key is that your career decisions become less about accumulation and more about how you want to spend your working years.
Continue Investing for a Larger Margin of Safety
Coast FIRE calculations rely on assumptions about future returns and withdrawal rates. Markets do not deliver consistent annual returns, and sequence-of-returns risk can impact your actual retirement outcome. Continuing to invest even modestly after reaching Coast FIRE provides a buffer against underperformance, unexpected expenses, or changes in your retirement plans.
Focus on Other Financial Goals
With retirement on autopilot, you can redirect savings toward other priorities. This might include paying off your mortgage early, building a larger emergency fund, saving for your children's education, funding travel, or investing in experiences that improve your quality of life today.
Keep Your Investments on Track
Even though you are no longer contributing, your portfolio still needs occasional attention. Rebalance your asset allocation periodically to maintain your target risk level. As you approach retirement, consider gradually shifting toward a more conservative allocation to reduce the impact of a market downturn in the years just before you begin withdrawals.
Frequently Asked Questions
What is a safe withdrawal rate and why does this calculator default to 4%?
The safe withdrawal rate is the percentage of your portfolio you can withdraw each year in retirement with a high probability of not running out of money. The 4% rule comes from the Trinity Study, which found that a diversified portfolio of stocks and bonds could sustain 4% annual withdrawals (adjusted for inflation) over a 30-year retirement period in most historical scenarios. While the 4% rule is a widely used starting point, some financial planners recommend 3.5% for more conservative planning or 4.5% if you have flexibility to reduce spending during market downturns.
Does Coast FIRE account for inflation?
This calculator uses a nominal return rate, so you should account for inflation by using a real (inflation-adjusted) return rate. If you expect 10% nominal returns and 3% inflation, enter 7% as your expected annual return. Similarly, enter your annual spending in today's dollars. Using real returns ensures your Coast FIRE number reflects actual purchasing power rather than inflated future dollars that may buy less than you expect.
What if the stock market underperforms my expected return?
Market underperformance is a real risk with Coast FIRE. If your investments return less than expected over the growth period, your portfolio may fall short of the target nest egg. To mitigate this risk, consider using a conservative return estimate (such as 5-6% real return instead of 7%), continuing to make at least small contributions after reaching Coast FIRE, and periodically recalculating your Coast FIRE status with updated portfolio values. Building a margin of safety by saving beyond your Coast FIRE number is one of the most effective strategies.
Can I reach Coast FIRE if I started investing late?
Yes, but it requires more aggressive saving in the near term. If you start investing at 40 and want to retire at 65, you have 25 years of growth instead of 35 or 40. That means your Coast FIRE number will be higher relative to your target nest egg because there is less time for compounding. The math still works, but you may need to save a larger percentage of your income for several years to accumulate enough. The good news is that higher earners in their 40s and 50s often have the income to make catch-up contributions and reach Coast FIRE faster than they expect.
Should I include Social Security in my Coast FIRE calculation?
It depends on your planning approach. If you expect Social Security to cover a portion of your retirement expenses, you can reduce the annual spending figure in the calculator by your expected Social Security benefit. For example, if you plan to spend $50,000 per year and expect $20,000 from Social Security, you would enter $30,000 as your annual spending. However, many FIRE planners prefer to exclude Social Security as a conservative measure, treating any benefits received as an additional safety margin rather than a core part of the plan.
