Include 401k, IRA, brokerage — anything invested for retirement.
Not sure? Use your annual expenses x 25. Example: $40,000/year x 25 = $1,000,000.
7% is a common estimate for a diversified index fund portfolio after inflation.
What Is Coast FIRE?
This coast fire calculator is built around one simple idea: you may already have enough invested to retire comfortably, even if you never add another dollar. Coast FIRE is a milestone on the path to financial independence, and this coast fire calculator helps you find out exactly where you stand. Once you hit your Coast FIRE number, compound growth does the heavy lifting from that point forward.
Regular FIRE (Financial Independence, Retire Early) means saving until your portfolio is large enough to support your full lifestyle right now. Coast FIRE is different. It means you have saved enough today that, if you leave it alone and let it grow at a reasonable rate, it will reach your full FIRE number by the time you want to retire. You do not need to contribute anything more. You still work, but only to cover your current living expenses, not to fund your future retirement.
This matters a lot for people who want more freedom now. Once you hit Coast FIRE, you can switch to a lower-paying job you actually enjoy, go part-time, take a sabbatical, or move somewhere cheaper. The pressure to maximize your savings rate every single year goes away. Your future is already funded. All you need to do is cover today.
Coast FIRE is popular because it is achievable much earlier than full FIRE. If you started saving aggressively in your 20s or early 30s, you may already be coasting without knowing it. Plug your numbers into the calculator above and find out where you stand right now.
How the Coast FIRE Calculator Works
The calculator asks for five inputs. Here is what each one means and why it matters.
Current Age is how old you are today. Target Retirement Age is when you want to stop working. The gap between these two numbers is how many years your investments have to grow. More years means less money you need today to reach your goal.
Current Savings and Investments is the total you have already invested for retirement. Include your 401k, IRA, brokerage accounts, and anything else that is invested and growing. Do not include your emergency fund or money sitting in a savings account — those are not compounding toward retirement.
Your FIRE Number is the portfolio size you need to retire. Expected Annual Return is the average yearly growth rate you expect from your investments. The default is 7%, which is a standard inflation-adjusted estimate for a diversified index fund portfolio.
The formula is straightforward: your Coast FIRE number equals your FIRE number divided by compound growth over your remaining years. In math terms: Coast Number = FIRE Number / (1 + r)^n, where r is your annual return rate and n is years until retirement.
As a concrete example: a 30-year-old targeting $1,000,000 at age 65 with a 7% annual return needs roughly $131,500 today to coast. If they have $131,500 invested right now and never add another cent, it will grow to $1,000,000 by the time they turn 65. That is the power of 35 years of compound growth.
What Is a FIRE Number?
Your FIRE number is the total portfolio value you need to retire and live off your investments indefinitely. The most common way to calculate it is the 25x rule, which comes from the widely cited Trinity Study. The idea is simple: if your annual expenses are X, you need 25 times X invested. A portfolio that size can sustain a 4% annual withdrawal rate, which historically has lasted 30 or more years without running out of money.
If you spend $40,000 per year, your FIRE number is $1,000,000 ($40,000 x 25). If you spend $60,000 per year, your FIRE number is $1,500,000. If you plan to cut expenses dramatically in retirement, your FIRE number shrinks. If you want to maintain a higher lifestyle or retire extra early, it grows.
Getting to your FIRE number is all about consistent, long-term investing. Two tools that can help: the DCA calculator shows how dollar-cost averaging into index funds compounds over time, and the DRIP calculator shows how reinvesting dividends accelerates growth. Both strategies feed the same goal: building a portfolio large enough to retire on your terms.
The 25x rule is a starting point, not a guarantee. Personal factors like healthcare costs, Social Security income, part-time work in early retirement, and your own risk tolerance all affect the right number for you. But for planning purposes, 25x is a solid benchmark used by millions of people working toward financial independence.
What Return Rate Should I Use?
The calculator defaults to 7%, and for most people planning a long-term index fund strategy, that is a reasonable starting point. Here is why.
The S&P 500 has returned about 10% per year on average before inflation over the long run. After adjusting for inflation (typically around 2-3% per year), the real return drops to roughly 7%. Since your FIRE number is based on today’s dollars and your cost of living in today’s dollars, using the inflation-adjusted return gives you a more accurate picture of what your money can actually buy when you retire.
If you are more conservative or closer to retirement, you might use 5-6% to account for a more balanced portfolio with some bonds. If you are young with a 100% equity portfolio and a high risk tolerance, some people use 8-9%. Changing the return rate has a significant impact on your Coast FIRE number — a higher rate means you need less saved today, and a lower rate means you need more.
For a deeper look at the Coast FIRE concept and how return rates factor into the math, Coast FIRE explained on Investopedia is a solid external reference. Try running the calculator at a few different return rates to see a range of outcomes rather than relying on a single number.
Frequently Asked Questions
Regular FIRE means you save until your portfolio is big enough to cover your living expenses right now. Coast FIRE means you have saved enough that compound growth will get you there by retirement age, even if you stop adding money today. You still work, but only to pay current bills, not to save for retirement.
The S&P 500 has averaged about 10% per year before inflation over the long run. After adjusting for inflation, 7% is a commonly used estimate. No one can promise future returns, but 7% is a reasonable middle ground for long-term planning with a diversified index fund portfolio.
Keep investing. The gap between your current savings and your Coast FIRE number is exactly how much more you need before you can stop contributing. Even small extra contributions each month will close that gap faster than you think, thanks to compound growth.
Barista FIRE is a variation where you semi-retire to a part-time job that covers your living expenses while your investments compound on their own. If you have hit your Coast FIRE number, a Barista FIRE approach lets you enjoy more freedom now while still staying on track for full retirement later.
Yes, but use a conservative return rate. Crypto is more volatile than stocks, so many people use 10-15% for optimistic projections and 5-7% for conservative ones. Try both and see the range of outcomes.
Ready to Start Coasting?
Coast FIRE is one of the most motivating milestones in personal finance because it gives you permission to breathe. Once your investments are large enough to grow on their own to your retirement goal, the pressure is off. You keep working to pay your bills, but you are no longer racing to save as much as possible every month. Compound growth is doing the work for you.
The key is to get there. Keep investing consistently, even when markets are down. Time in the market beats timing the market. Every dollar you add today has more years to compound than a dollar added next year. The earlier you hit your Coast FIRE number, the earlier you get your freedom back.
Some people choose to accelerate the journey by allocating a portion of their portfolio to higher-growth assets. More growth potential means reaching the Coast FIRE number faster, though it also means accepting more volatility. If you want to grow your investments faster, Bitunix lets you get started without KYC.
Your next step: run the calculator with your real numbers. If you are already at or near your Coast FIRE number, that changes how you think about your job, your savings rate, and your next career move. If you are not there yet, the gap tells you exactly what you are working toward. Either way, knowing your number is the start.