A 30-year-old with $94,000 invested today — and zero additional contributions — would reach $1 million by age 65. No 401(k) match needed. No aggressive savings rate. No side hustles. Just compound growth doing what it does over 35 years.
That’s coast FIRE in one sentence.
Most people hear “financial independence” and picture decades of extreme frugality. Coast FIRE flips that script. Save hard early, hit one number, then stop. Your money grows to your retirement target on autopilot. You still work — but only to cover today’s expenses, not tomorrow’s nest egg.
This guide covers the formula, a calculator to find your exact number, and an age-by-age table so you can see where you stand right now.
Coast FIRE Calculator
Your number depends on four things: how much you spend, when you want to retire, what’s already invested, and how fast those investments grow. Plug in your numbers below.
💡 How to Use This Calculator
- 1. Annual Spending — your expected yearly expenses in retirement (today's dollars).
- 2. Currently Invested — total in 401(k), IRA, Roth, and brokerage. Not home equity or checking.
- 3. Current Age / Retirement Age — more years = lower coast number (more time to compound).
- 4. Expected Real Return — 7% is the historical U.S. stock average after inflation. Use 5–6% for conservative.
- 5. Withdrawal Rate — 4% is the standard from the Trinity Study. Lower = safer but higher target.
What Coast FIRE Actually Means
Coast FIRE is a milestone — not a finish line. You reach it when your current investments, left alone with no new contributions, will grow to cover your retirement through compound interest.
The key word is current. Once you’ve accumulated enough, time and market returns do the rest. You shift from building wealth to maintaining lifestyle.
This is different from traditional FIRE, which requires accumulating 25× your annual spending before you stop working entirely. This approach only requires enough invested today for compound growth to reach that target by your retirement age — typically a fraction of the full amount.
The Coast FIRE Formula
Two steps. That’s it.
Step 1 — Find your FIRE Number. Take your expected annual spending in retirement and multiply by 25. This comes from the 4% safe withdrawal rate, based on the Trinity Study research showing a high success rate over 30-year retirement horizons.
Spending $40,000/year → FIRE Number = $1,000,000
Spending $50,000/year → FIRE Number = $1,250,000
Spending $60,000/year → FIRE Number = $1,500,000
Step 2 — Discount backwards. Divide your FIRE Number by how much compound growth will multiply your money between now and retirement.
Example: A 30-year-old planning to retire at 65 who needs $40,000/year:
Coast FIRE = $1,000,000 ÷ (1.07)35 = $1,000,000 ÷ 10.68 = $93,663
If this person has $94,000 invested in a diversified portfolio today, compound growth alone handles the rest. No more retirement contributions needed — assuming historical market returns continue.
Coast FIRE Number by Age
This table uses a 7% real return (roughly 10% nominal minus 3% inflation), a 4% safe withdrawal rate, and a retirement age of 65. Your number changes based on how many compounding years remain.
| Current Age | Years to 65 | $40K Spending | $50K Spending | $60K Spending |
|---|---|---|---|---|
| 25 | 40 | $66,780 | $83,475 | $100,171 |
| 30 | 35 | $93,663 | $117,079 | $140,494 |
| 35 | 30 | $131,367 | $164,209 | $197,051 |
| 40 | 25 | $184,249 | $230,311 | $276,374 |
| 45 | 20 | $258,419 | $323,024 | $387,629 |
The pattern is stark. A 25-year-old needs $66,780 to coast to $1 million. A 45-year-old needs $258,419 — nearly four times more. Every year you wait, the number climbs because compound growth has less time to work.
This table assumes 7% real returns — which is the historical average for a diversified U.S. stock portfolio after inflation. If you use a more conservative 6% real return, add roughly 30-40% to each number. The FIRE Number Calculator lets you test different assumptions.
Coast FIRE vs Other FIRE Variations
It’s the most achievable milestone in the FIRE spectrum. It doesn’t require you to quit your job or live on rice and beans. It’s a single checkpoint: once you pass it, retirement is solved — and the psychological relief alone is worth the sprint.
How to Reach Coast FIRE Faster
The target number is a function of time and savings rate. You can’t control market returns, but you can control how fast you get to the finish line.
Maximize Tax-Advantaged Accounts First
In 2026, the IRS contribution limits are $24,500 for 401(k) plans and $7,500 for IRAs. That’s $32,000 per year in tax-advantaged space — before counting employer matches. A 25-year-old who maxes both for five years would have roughly $160,000 invested by age 30. That already exceeds the target for $40K annual spending.
Focus on Savings Rate, Not Returns
A 30% savings rate gets you there faster than chasing an extra 2% return. The savings rate is the only variable you fully control. Earning $70,000 and saving 30% means $21,000/year invested — enough to hit the $94,000 mark for a 30-year-old in under five years with modest growth.
Keep Investment Costs Near Zero
The difference between a 0.03% expense ratio (VOO) and a 1% managed fund might seem trivial. Over 35 years of compounding, that fee gap erodes tens of thousands from your long-term trajectory. Broad index funds — VTI, VOO, or their index mutual fund equivalents — keep costs minimal and exposure diversified.
Don’t Include Your Home
These numbers should reflect invested, liquid assets only. Your primary residence doesn’t count — you need somewhere to live in retirement too. Include 401(k) balances, IRAs, Roth accounts, and taxable brokerage investments. Exclude home equity, cars, and savings earmarked for near-term goals.
What If Returns Are Lower Than Expected?
The 7% real return assumption is historically grounded, but it’s still an assumption. Here’s what the numbers look like at a more conservative 6% real return:
| Age | $40K (7% real) | $40K (6% real) | Difference |
|---|---|---|---|
| 25 | $66,780 | $97,222 | +$30,442 |
| 30 | $93,663 | $130,105 | +$36,442 |
| 35 | $131,367 | $174,110 | +$42,743 |
| 40 | $184,249 | $232,999 | +$48,750 |
| 45 | $258,419 | $311,805 | +$53,386 |
A single percentage point in returns adds $30,000–$53,000 to your target number. That’s why running the calculator with conservative assumptions matters more than optimizing for an extra 1% return. Plan for 6%, hope for 7% — and anything above that becomes a bonus.
What Life Looks Like After Coast FIRE
Reaching this milestone doesn’t mean you stop working. It means you only need to earn enough to cover current living expenses. The retirement piece is handled.
That opens up a range of choices that weren’t available before:
3 Coast FIRE Mistakes That Cost Years
Coast FIRE: Frequently Asked Questions
What is coast FIRE?
Coast FIRE is a financial milestone where your current investments — without any additional contributions — will grow to support your retirement by a target age (typically 65). After reaching it, you only need to earn enough to cover current living expenses. Your retirement funding is handled by compound growth alone.
How much do I need for coast FIRE?
It depends on your age, retirement spending target, and return assumptions. A 30-year-old expecting to spend $40,000/year in retirement needs roughly $94,000 invested today (assuming 7% real returns and a 4% safe withdrawal rate). A 40-year-old with the same spending target needs about $184,000. Use the calculator above for your specific numbers.
Is 7% a realistic return assumption?
The S&P 500 has returned approximately 10% annually since 1926. After adjusting for ~3% average inflation, the real return is roughly 7%. It’s a commonly used assumption in the FIRE community, though more conservative planners use 5-6%. Higher return assumptions shrink the target number but increase risk if markets underperform.
What happens if the market crashes after I reach coast FIRE?
A significant downturn early in your coasting period can delay the timeline. Building a 10-20% buffer above your calculated target helps absorb market drops. You can also resume contributions temporarily if your portfolio falls below target — the flexibility is the entire point.
Can I still save after reaching coast FIRE?
Absolutely. Coast FIRE is a minimum threshold, not a maximum. Many people continue contributing at a reduced rate after reaching the milestone. Extra savings accelerate the timeline toward full financial independence or provide a larger safety margin.
This article is for informational purposes only and does not constitute investment advice. The calculations shown assume historical average returns, which are not guaranteed to continue. Always do your own research or consult a licensed financial advisor before making investment decisions.