Most people who discover the FIRE movement have the same initial reaction: the math makes sense, but saving 50% or more of my income for a decade sounds brutal. Traditional FIRE demands years of aggressive saving — and for many people, it requires sacrifices that are not sustainable.
Coast FIRE flips the script. Instead of sprinting to a finish line where your portfolio covers all living expenses forever, you front-load your investing early, then stop contributing entirely. Compound growth does the remaining work over the next 25 to 35 years while you only earn enough to cover day-to-day expenses. No more obsessing over savings rates. You coast.
This guide explains exactly what Coast FIRE is, walks through the formula, provides concrete examples at different ages, and lays out what life looks like after you reach your number. If traditional FIRE feels like running a marathon at sprint pace, Coast FIRE is running the first five miles hard and walking the rest.
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Table of Contents
- What Is Coast FIRE?
- The Coast FIRE Formula
- Coast FIRE Numbers by Age
- How to Calculate Your Coast FIRE Number
- What to Do After Reaching Coast FIRE
- Coast FIRE vs. Regular FIRE vs. Barista FIRE
- How to Reach Coast FIRE Faster
- Common Coast FIRE Mistakes
- Frequently Asked Questions
- The Bottom Line
What Is Coast FIRE?
Coast FIRE is the point at which you have saved and invested enough money that compound growth alone — with zero additional contributions — will grow your portfolio to your full retirement target by a traditional retirement age (typically 60 to 67).
Once you reach Coast FIRE, you no longer need to save for retirement. You still need income to pay rent, buy groceries, and cover insurance. But every dollar you earn can go toward current living expenses. The retirement problem is already solved. Your invested assets are compounding in the background, doubling roughly every ten years at a 7% average annual return.
Here is a concrete example. Say your target retirement portfolio is $1,000,000 at age 65. If you are 25 years old and have $85,000 invested in a diversified index fund portfolio earning an average 7% annually, that $85,000 will grow to approximately $1,140,000 over 40 years — without you adding another cent. At 25, your Coast FIRE number is roughly $85,000.
That number changes based on your age, your expected rate of return, and your retirement target. But the principle is always the same: save hard now, and let time and compounding do the rest.
Why Coast FIRE is gaining popularity
Coast FIRE has become the fastest-growing FIRE variant for several reasons:
- It is achievable on a normal salary. You do not need a six-figure tech income. A 25-year-old earning $55,000 who saves aggressively for three to five years can hit their Coast FIRE number.
- It does not require decades of deprivation. The intense saving phase is short — typically 5 to 10 years — and then you can relax.
- It solves the biggest FIRE objection. "I do not want to live like a monk for 15 years" does not apply when the aggressive phase lasts only a fraction of that time.
- It pairs well with career changes. After reaching Coast FIRE, you can switch to lower-paying but more fulfilling work without jeopardizing your retirement.
The Coast FIRE Formula
The math behind Coast FIRE is straightforward. It uses the future value of a lump sum — the same compound interest formula you learned in a finance or math class:
FV = PV x (1 + r)^n
Where:
- FV = Future Value (your retirement target, e.g., $1,000,000)
- PV = Present Value (the amount you need invested today — your Coast FIRE number)
- r = Annual rate of return (typically 7% nominal for a stock-heavy portfolio)
- n = Number of years until your target retirement age
To find your Coast FIRE number, you rearrange the formula to solve for PV:
PV = FV / (1 + r)^n
So if your retirement target is $1,000,000, you expect 7% annual returns, and you have 30 years until retirement:
PV = $1,000,000 / (1.07)^30 PV = $1,000,000 / 7.612 PV = $131,367
That means a 35-year-old who wants $1,000,000 at age 65 needs approximately $131,000 invested today. Once they hit that number, they never need to contribute to retirement again.
Choosing your assumptions
Retirement target. Use the 4% rule backward: multiply your desired annual retirement spending by 25. Want $40,000/year? Your target is $1,000,000. Want $60,000/year? You need $1,500,000.
Rate of return. The S&P 500 has returned approximately 10% annually before inflation and roughly 7% after inflation since 1926. Most Coast FIRE calculations use 7% nominal. Some planners prefer 6% for an additional safety margin. Do not use 10% — it overstates growth and understates what you need to save.
Retirement age. Most calculations use 65. A target age of 60 requires more saved today; 67 requires less.
Coast FIRE Numbers by Age
The table below shows approximate Coast FIRE numbers at various ages, assuming a $1,000,000 retirement target at age 65 and a 7% average annual return.
| Current Age | Years to 65 | Coast FIRE Number | Growth Multiple |
|---|---|---|---|
| 22 | 43 | $71,000 | 14.08x |
| 25 | 40 | $85,000 | 11.76x |
| 28 | 37 | $104,000 | 9.61x |
| 30 | 35 | $115,000 | 8.69x |
| 32 | 33 | $127,000 | 7.87x |
| 35 | 30 | $155,000 | 6.45x |
| 38 | 27 | $190,000 | 5.26x |
| 40 | 25 | $215,000 | 4.65x |
| 45 | 20 | $295,000 | 3.39x |
| 50 | 15 | $410,000 | 2.44x |
Key takeaways from these numbers:
Youth is an enormous advantage. A 22-year-old needs only $71,000 — achievable within two to four years of starting a career with aggressive saving.
Every year of delay is expensive. Waiting from 25 to 30 increases your number by $30,000. From 30 to 35 adds another $40,000. The compounding penalty for procrastination accelerates.
After 40, the window narrows. Coast FIRE at 45 or 50 is possible, but the numbers approach what traditional FIRE requires. Coast FIRE is most powerful when you start in your twenties or early thirties.
Adjusting for a higher retirement target
If your retirement spending goal is higher than $40,000 per year, your Coast FIRE number scales proportionally:
| Current Age | $1M Target (40K/yr) | $1.25M Target (50K/yr) | $1.5M Target (60K/yr) | $2M Target (80K/yr) |
|---|---|---|---|---|
| 25 | $85,000 | $106,000 | $128,000 | $170,000 |
| 30 | $115,000 | $144,000 | $173,000 | $230,000 |
| 35 | $155,000 | $194,000 | $233,000 | $310,000 |
| 40 | $215,000 | $269,000 | $323,000 | $430,000 |
How to Calculate Your Coast FIRE Number
Follow these five steps to determine your personal Coast FIRE number:
Step 1: Determine your retirement spending target
Estimate how much you want to spend annually in retirement. If you are unsure, a common starting point is your current annual spending minus work-related costs (commuting, professional wardrobe, payroll taxes). For most people, this lands between $35,000 and $70,000 per year.
Step 2: Calculate your retirement portfolio target
Multiply your annual retirement spending by 25 (based on the 4% safe withdrawal rate). If you want a more conservative plan, multiply by 28.6 (3.5% withdrawal rate).
- $40,000/year x 25 = $1,000,000
- $50,000/year x 25 = $1,250,000
- $60,000/year x 25 = $1,500,000
Step 3: Choose your expected return rate and retirement age
Use 7% for a stock-heavy portfolio or 6% if you want a safety buffer. Set your target retirement age — 65 is standard, but adjust based on your plans.
Step 4: Run the formula
Divide your retirement target by (1 + return rate) raised to the power of years until retirement.
Coast FIRE Number = Retirement Target / (1.07)^(years to retirement)
Step 5: Compare to your current portfolio
If your current invested assets (401k, IRA, brokerage accounts) equal or exceed your Coast FIRE number, congratulations — you have reached Coast FIRE. If not, the gap between your current portfolio and your Coast FIRE number tells you exactly how much more you need to save.
(affiliate) Automate the path to your Coast FIRE number. Betterment makes it simple to set up automatic recurring investments into a diversified, low-cost portfolio. Their goal-based tools let you set a specific target amount — your Coast FIRE number — and track your progress in real time. Once you reach your number, you can pause contributions and let compounding take over. For Coast FIRE specifically, Betterment's automated approach removes the temptation to tinker during the accumulation phase, which is exactly what you want.
What to Do After Reaching Coast FIRE
Reaching Coast FIRE is a milestone, but it is not retirement. You still need income to cover current living expenses. The difference is that the income only needs to cover today — not today plus retirement savings. That distinction changes everything about how you think about work.
Downshift your career
Stay in your current field but negotiate reduced hours. A software engineer might move to three days per week. A nurse might drop from five shifts to three. The pay cut does not matter for retirement — that box is already checked — so you are trading income for time.
Switch to passion-driven work
When your job only needs to cover rent and groceries, careers that were previously "impractical" become viable. Teachers, nonprofit workers, freelance writers, and park rangers do not earn six figures — but they do not need to. Coast FIRE gives you permission to optimize for meaning instead of money.
Start a business with lower risk
After Coast FIRE, the risk calculus changes. Your retirement is funded. If the business fails, you are back to a regular job — not broke. Many Coast FIRE practitioners use this window to start small businesses or creative ventures they would never have attempted otherwise.
Go part-time or seasonal
Some Coast FIRE practitioners work only part of the year — seasonal tourism jobs, tax-season accounting, or summer camp counseling — and take the rest off. Others work part-time year-round, maintaining structure without the grind of 40+ hour weeks.
Continue investing (optional acceleration)
Any post-Coast FIRE contributions accelerate your timeline, potentially allowing you to reach full FIRE years or decades earlier. Some practitioners coast for a few years, recharge, and then resume saving at a moderate pace — reaching full financial independence in their late forties or fifties instead of 65.
Coast FIRE vs. Regular FIRE vs. Barista FIRE
These three FIRE variants are often confused. Here is how they differ:
| Coast FIRE | Regular (Traditional) FIRE | Barista FIRE | |
|---|---|---|---|
| Goal | Save enough that compound growth funds retirement — earn only for current expenses | Save enough that your portfolio covers all living expenses immediately | Save enough that you only need part-time income to cover the gap |
| When you stop saving for retirement | At your Coast FIRE number (can be in your 20s or 30s) | At your full FIRE number (25x annual expenses) | At a partial FIRE number (often 50–70% of full FIRE) |
| Income needed after milestone | Enough to cover current living expenses | None (work is optional) | Part-time income to supplement portfolio withdrawals |
| Typical portfolio at milestone | $85K–$300K (age-dependent) | $625K–$2.5M+ | $300K–$750K |
| When you fully retire | Traditional retirement age (60–67) | Immediately (often 35–50) | Immediately, but with part-time work |
| Primary advantage | Easiest to achieve; reduces pressure earliest | Complete financial freedom | Balances freedom with a lighter work schedule |
| Primary drawback | Does not provide immediate retirement | Requires the most aggressive saving | Still requires some earned income |
Which one is right for you?
Choose Coast FIRE if you are young (under 35), want to remove retirement anxiety quickly, and are happy working in some capacity — just not at maximum intensity.
Choose regular FIRE if your primary goal is to stop working entirely as soon as possible and you can maintain a 40%+ savings rate for an extended period.
Choose Barista FIRE if you want to leave a high-stress career soon but are comfortable with part-time work — particularly appealing if you want employer health insurance through a part-time role (Starbucks, Costco, REI).
For a deeper comparison of all FIRE types, see our complete FIRE movement guide.
How to Reach Coast FIRE Faster
Maximize tax-advantaged accounts first
Contribute to your 401(k) at least up to the employer match (an instant 50-100% return), then max out a Roth IRA ($7,000 in 2026). Tax-advantaged accounts compound more efficiently because gains are not eroded by annual capital gains taxes.
Automate your investments
Set up automatic transfers from each paycheck into your investment accounts. Automation removes decision fatigue and ensures consistent investing even when motivation dips.
(affiliate) Betterment is built for exactly this approach. You can schedule automatic deposits on your payday, and Betterment's algorithms handle diversification, rebalancing, and tax-loss harvesting automatically. For Coast FIRE accumulators who want a hands-off system that quietly builds wealth, this is one of the most effective tools available. Their tax-loss harvesting alone can add an estimated 0.77% in annual after-tax returns — which meaningfully accelerates how fast you reach your Coast FIRE number.
Keep lifestyle inflation in check
The biggest threat to Coast FIRE is not bad returns — it is earning more and spending more. Direct raises into investments before upgrading your lifestyle.
Use windfalls strategically
Tax refunds, bonuses, and side hustle income can close the gap in chunks. A single $10,000 windfall invested at 25 becomes roughly $150,000 by age 65 at 7% growth. Treat windfalls as retirement fuel, not spending money.
Start a side hustle during the accumulation phase
Even $500 to $1,000 per month from a side hustle can cut years off your timeline. If your day job covers expenses, every side dollar goes directly toward your Coast FIRE number.
Common Coast FIRE Mistakes
Using overly optimistic return assumptions
Plugging in 10% or 12% annual returns makes your Coast FIRE number look tantalizingly low — and dangerously unrealistic. Use 7% or lower. Being conservative means you either hit your target or beat it. Being aggressive means you might fall short with no time to recover.
Ignoring inflation in your retirement target
If you want $40,000 in today's purchasing power at age 65, your nominal target needs to be higher than $1,000,000. One approach: use 7% nominal returns with a nominal spending target that accounts for inflation. Another: use real returns of 4-5% and keep everything in today's dollars. Pick one method and be consistent.
Forgetting about healthcare
After Coast FIRE, if you leave a traditional job, you lose employer-sponsored health insurance. ACA marketplace plans can run $400 to $1,500+ per month depending on your income and state. Factor healthcare costs into the "current expenses" you need your post-Coast FIRE income to cover.
Counting non-invested assets
Your Coast FIRE number refers to invested, growth-oriented assets — not your emergency fund, home equity, or checking account. Only count money actually invested in diversified portfolios compounding at market rates.
Reaching the number and then withdrawing
People hit their Coast FIRE number and then dip into the portfolio for a home purchase or emergency. Every dollar withdrawn resets the compounding clock. Your Coast FIRE number only works if you leave it invested.
The Bottom Line
Coast FIRE is the most accessible entry point into financial independence. It does not demand a six-figure salary, a 60% savings rate, or a decade of extreme frugality. It demands a short, intense period of focused saving — typically three to eight years — followed by the freedom to let compound growth finish the job.
The formula is simple: FV = PV x (1 + r)^n. The execution requires discipline but not deprivation. Max out tax-advantaged accounts, automate your investments, resist lifestyle inflation during the accumulation years, and leave your portfolio alone once you hit your number.
What makes Coast FIRE genuinely life-changing is what happens after the math. When retirement is handled, your relationship with work fundamentally shifts. You can teach, create, volunteer, freelance, or simply work less. Career decisions that used to be constrained by retirement anxiety become open-ended.
If you are in your twenties or early thirties and traditional FIRE feels overwhelming, start with Coast FIRE. Reach your number. Let compound interest do what it does. Then spend the next 30 years deciding what you actually want to do with your time.
(affiliate) Ready to start building toward your Coast FIRE number? Betterment offers automated investing with tax-loss harvesting, goal tracking, and zero-commission trades. Set your Coast FIRE target, automate your deposits, and let the platform handle the rest. It takes about five minutes to set up, and once your portfolio reaches your number, you can stop contributing and coast.
Disclaimer {#disclaimer}
This article is for informational purposes only and does not constitute financial advice. Affiliate links in this article may generate a commission for Deep Learning Finance at no additional cost to you. Investment returns are not guaranteed — the 7% average annual return used throughout this article is based on historical S&P 500 performance and may not reflect future results. All investments carry risk, including the potential loss of principal. Consult a qualified financial advisor before making investment decisions based on your individual circumstances.
This content falls under Your Money or Your Life (YMYL) guidelines. We take accuracy seriously and update this article regularly. Tax laws, contribution limits, and financial regulations change frequently. Always verify current figures with official IRS publications and regulatory sources.