Coast FIRE Calculator — Find When You Can Stop Contributing
Figure out the portfolio you need today so future compounding does the rest by retirement, even if you stop adding new savings.
Coast FIRE Number
$157,641
Full FIRE Number
$1,200,000
Coast FIRE status
Not yet
Coasting income
$48,000
Timeline
Today
30
2026
Coast FIRE
33.5
2029
Retirement
60
2056
At your current pace, you reach Coast FIRE in about 3.5 years, around October 2029.
Coast FIRE is a financial independence milestone where your current invested portfolio is large enough that compound growth alone will carry it to your full retirement target by a chosen age, even if you never contribute another dollar. Once you reach your Coast FIRE number, you only need to earn enough to cover current living expenses. The concept relies on the historical power of compounding: the S&P 500 has returned approximately 10.3% annually since 1926 (about 7% after inflation), according to NYU Stern data.
How This Calculator Works
The Coast FIRE calculator planning starts with one core question: how much portfolio capital must eventually replace your paycheck? This page answers that question by translating your spending target, investment return assumption, and withdrawal rule into a concrete capital requirement. The calculator uses monthly compounding instead of rough annual shortcuts, which matters because real portfolios grow and contributions land throughout the year. If you are learning the broader FIRE math for the first time, the quickest companion read is our guide on how to calculate your FIRE number, because it explains why spending is the engine behind every retirement target.
Under the hood, the main formula on this page is Coast FIRE number = full FIRE number divided by (1 + real return) raised to the years until retirement. From there, the calculator iterates month by month until your portfolio reaches the required threshold. That approach is more faithful than a back-of-the-envelope estimate because it captures the timing of contributions, compounding, and the nonlinear way returns accelerate once the portfolio gets larger. It also means small changes in monthly savings or return assumptions can shift your timeline materially, which is why the tool updates live as you move sliders and revise spending inputs.
If your full FIRE number is $1.2 million and you have thirty years until retirement with a 7% real return assumption, the Coast FIRE target today is dramatically smaller because compounding does the rest of the heavy lifting. The point is not that one formula can predict the future with perfect accuracy. The point is that a disciplined framework lets you compare scenarios on equal footing. When you change the withdrawal rate from 4% to 3.5%, or reduce planned annual spending by a few thousand dollars, you are not guessing anymore. You are seeing the capital effect directly and understanding which variables deserve your attention first.
Understanding Your Results
The result tells you whether your current portfolio already has enough momentum to reach full FIRE without any new retirement contributions. The most important output is the headline target, but it is not the only one that matters. The years-to-retirement estimate shows how long your current system takes to close the gap. The FI date converts the abstract number into a calendar milestone, which is often more motivating than a raw dollar figure. The inflation-adjusted target reminds you that a million dollars today is not the same as a million dollars twenty years from now, even when you are using real returns for planning.
You should also read the results as a range of plausibility, not as a promise. A projection based on steady real returns can still be disrupted by sequence-of-returns risk, especially early in retirement when withdrawals begin. That is why this site pairs deterministic math with Monte Carlo analysis on the primary FIRE calculator. If the target looks achievable but the success rate is weak, the plan may be mathematically possible while still being too fragile for comfort. In practice, robust plans combine a realistic spending target, a conservative withdrawal rule, and enough flexibility to cut expenses or earn supplemental income if markets disappoint.
A good outcome depends on context. Someone targeting Coast FIRE may gladly accept a leaner lifestyle for more freedom, while someone pursuing a longer or more luxurious retirement may intentionally choose a slower path. The correct read is not whether your timeline is fast or slow in absolute terms. It is whether the timeline fits the life you want and whether the assumptions leave enough margin for inflation, taxes, healthcare, and market volatility. The calculator helps you see those tradeoffs clearly so you can refine the plan rather than react emotionally to a single number.
How to Improve Your FIRE Date
To hit Coast FIRE sooner, focus on front-loading investment contributions during the years when each dollar has the longest runway. Early compounding matters much more here than squeezing out marginal gains later in life. In most cases, the biggest improvement comes from raising your savings rate because that creates a double benefit: you invest more today and, by definition, you need less spending to support tomorrow. The second lever is expenses. Each recurring dollar you remove from planned retirement spending lowers the target portfolio by roughly twenty-five dollars at a 4% withdrawal rate, which is why housing, transportation, and location choices usually matter more than minor budgeting tweaks.
Returns matter, but they should be handled with humility. Chasing higher expected returns by concentrating risk is usually a mistake. A better approach is broad-market index investing, tax efficiency, disciplined rebalancing, and staying invested long enough for compounding to work. Geographic arbitrage can also be powerful if it fits your life. Moving from a high-cost metro to a lower-cost city, lower-tax state, or international destination can reduce both current spending and future retirement needs. The strongest FIRE plans are rarely built by one dramatic move. They come from stacking several sensible decisions that improve flexibility and reduce fragility over time.
Frequently Asked Questions
What is a Coast FIRE number and how is it calculated?
Your Coast FIRE number is the portfolio balance you need today so that compound growth alone carries it to your full FIRE target by retirement age — with no further contributions required. The formula is: Coast FIRE number = full FIRE number ÷ (1 + real annual return)^(years until retirement). If your full FIRE target is $1.2 million, your real return assumption is 7%, and you have 30 years until retirement, your Coast FIRE number is approximately $157,000. Once you cross that threshold, you only need to earn enough to cover current living costs.
What investment return should I use in a Coast FIRE calculation?
The U.S. stock market has returned approximately 10.3% nominally since 1926, and roughly 7% after inflation, according to NYU Stern data. For Coast FIRE planning, real returns matter more than nominal returns because the calculation is expressed in today's dollars. A 7% real return is a reasonable central estimate for a broadly diversified equity portfolio, but it carries meaningful uncertainty over any specific 30-year window. Bengen's 1994 research and the subsequent Trinity Study used historical data from 1926–1995 as the basis for safe withdrawal analysis — that same data underlies most standard return assumptions.
Can a median-income household realistically reach Coast FIRE before 40?
Yes, but the path is narrower than it looks in generic examples. The U.S. median household income was approximately $80,610 in 2023 (U.S. Census Bureau). At a 30% savings rate on that income, and with a $50,000 annual retirement spending target, the Coast FIRE number using a 7% real return over a 25-year horizon is roughly $200,000. That is achievable in 7–9 years from a zero starting point, depending on investment returns. The difficulty is sustaining that savings rate while covering housing costs in most major metro areas.
What changes after I reach Coast FIRE — am I done?
Coast FIRE does not mean retirement. It means you no longer need to direct new savings toward the retirement portfolio. You still need to cover current living expenses from earned income. Many people use the milestone to shift careers — taking lower-paying work they find more meaningful, reducing hours, or moving to a lower cost-of-living location. The psychological effect is significant: the retirement outcome is now locked in by compounding, regardless of what you earn.
What is the difference between Coast FIRE and Barista FIRE?
The distinction is temporal. Coast FIRE describes a portfolio milestone — you have enough invested that growth handles the rest. Barista FIRE describes a lifestyle arrangement — you retire from full-time work but take part-time employment to cover current expenses while the portfolio compounds. Both involve the same underlying math, but Coast FIRE is a threshold and Barista FIRE is a strategy for what you do after crossing it.
Does the Coast FIRE calculator account for inflation in its results?
The calculator uses real (inflation-adjusted) returns by default, which means all figures are expressed in today's dollars. When you see a Coast FIRE number of $157,000, that is what you need now — not a nominal future value inflated by 20 years of price increases. If you prefer to see nominal figures, increase your expected return by your assumed inflation rate (typically 2–3%) to convert from real to nominal terms.