Coast FIRE Calculator

Find out if you’ve reached Coast FIRE — the point where you can stop saving and let your investments grow to retirement.

How to Use the Coast FIRE Calculator

Here’s what each input means and how to fill it in accurately:

• Current Age — Your age today. The younger you are, the lower your Coast FIRE number — your money has more time to compound.
• Target Retirement Age — When you want to stop working entirely. Traditional retirement is 65, but you can set any age.
• Annual Spending in Retirement — How much you expect to spend per year in retirement, in today’s dollars. Most people estimate 70–80% of their current income as a starting point.
• Expected Annual Return — The default of 7% reflects the historical inflation-adjusted return of a broad US stock market index. More conservative planners use 5–6%.
• Current Invested Assets — Your total in investment accounts: 401(k), IRA, Roth IRA, brokerage accounts. Exclude your primary home and emergency fund.
• Monthly Contributions — Set this to $0 if you want to check whether you’ve already hit Coast FIRE. Add your actual contributions to see how quickly you’ll get there if you haven’t.

Hit Calculate to see your Coast FIRE number, whether you’ve hit it yet, and your projected portfolio value at retirement.

What Is Coast FIRE?

Coast FIRE stands for Coast Financial Independence, Retire Early. It’s a milestone within the broader FIRE movement, and it works differently from traditional FIRE.

With standard FIRE, the goal is to accumulate enough invested assets to retire immediately — typically 25× your annual expenses. That’s a long, aggressive savings journey that requires setting aside 40–60% of income for years.

Coast FIRE is a different, earlier milestone. The idea: save aggressively in your early years, hit a specific target, then stop contributing to retirement entirely. From that point, your existing investments — left untouched — will compound on their own until they reach full retirement size by your target date. You still work to cover daily expenses, but the retirement savings pressure is completely off.

Think of it like pushing a boulder to the top of a hill, then stepping back and letting it roll the rest of the way. You did the hard work early. Now you coast.

The Coast FIRE Formula (How It’s Calculated)

The calculator uses two steps under the hood.

Step 1 — Find your full FIRE number:

This is the total portfolio you’ll need at retirement to withdraw from sustainably. The standard formula is based on the 4% safe withdrawal rate (the “4% rule”), which comes from historical research on portfolio longevity:

FIRE Number = Annual Retirement Spending × 25

If you plan to spend $50,000 per year in retirement, your FIRE number is $1,250,000.

Step 2 — Work backwards to find your Coast number:

Coast FIRE Number = FIRE Number ÷ (1 + Annual Return Rate) ^ Years Until Retirement

Using the example above: a 35-year-old targeting $1,250,000 by age 65 at 7% real returns needs:

$1,250,000 ÷ (1.07)^30 = approximately $164,000 today

If they have $164,000 invested right now and never contribute another dollar, their portfolio reaches $1,250,000 by 65. That’s Coast FIRE.

Coast FIRE Numbers by Age (Reference Table)

How much you need saved today depends heavily on your age. Every five-year delay adds roughly 40% to your required Coast number, because compound interest has less runway.

This table assumes a $1,500,000 retirement target at age 65 with 7% real annual returns — a common benchmark:

Current Age	Coast FIRE Number Needed
25	~$147,000
30	~$197,000
35	~$276,000
40	~$388,000
45	~$544,000
50	~$764,000

The takeaway is stark: a 25-year-old needs less than half of what a 40-year-old needs to hit the same retirement goal, purely because of time. Starting early is the single most powerful lever in Coast FIRE planning.

Adjust your own numbers in the calculator above — your retirement target and return assumptions will shift these figures.

What Happens After You Hit Coast FIRE?

Reaching your Coast FIRE number is a real financial milestone — but it doesn’t mean you stop working. It means you stop needing to save aggressively for retirement.

Here’s what most people do after hitting Coast FIRE:

Keep working the same job, but relax. You no longer need to maximize your 401(k) contributions or sacrifice lifestyle for retirement savings. That freed-up cash can go toward experiences, paying down debt, or simply having more financial breathing room month to month.

Downshift to less stressful work. Many people switch careers, take a lower-paying job they actually enjoy, or move to part-time hours. Since you’re only covering current expenses — not building a retirement portfolio — you need far less income.

Take time off or pursue passion projects. Without retirement savings pressure, a sabbatical, a career pivot, or launching a side business all become more financially viable.

The key constraint: you can’t withdraw from your investment accounts. The entire Coast FIRE strategy depends on leaving your portfolio completely untouched to compound. Any early withdrawals reset the clock.

Coast FIRE vs. Other FIRE Strategies

The FIRE movement includes several variations. Here’s how Coast FIRE compares:

Traditional FIRE — Accumulate 25× annual expenses, then retire immediately and live off investment withdrawals. Requires the highest savings rate and longest runway. Coast FIRE is a milestone on the way to this.

Barista FIRE — Similar to Coast FIRE in spirit. You work a part-time or lower-paying job — often specifically for employer health insurance benefits — while your portfolio grows. The name comes from the idea of working a coffee shop job for benefits rather than income.

Lean FIRE — Full retirement on a tight budget. You reach full FIRE but with a lower annual spending target (often under $40,000/year). Requires a smaller portfolio but demands lifestyle frugality.

Fat FIRE — Full retirement with a generous lifestyle budget, often $100,000+ per year in spending. Requires a much larger portfolio but offers maximum flexibility in retirement.

Coast FIRE sits between traditional saving and full financial independence. It’s arguably the most achievable first milestone for most people — especially those who started investing early and are already closer than they think.

Frequently Asked Questions

What is a Coast FIRE number?

Your Coast FIRE number is the specific dollar amount you need invested today — in accounts you won’t touch — for compound growth alone to reach your full retirement target by your chosen retirement age. Once your portfolio hits this number, you no longer need to contribute to retirement savings. The number depends on your age, retirement age, annual expenses in retirement, and your assumed investment return rate.

How is Coast FIRE different from regular FIRE?

Regular FIRE means accumulating enough to retire and live off withdrawals immediately. Coast FIRE is an earlier, lower target — you’ve saved enough that compound growth will eventually get you to full FIRE by traditional retirement age, but you’re not there yet. With Coast FIRE you still work to cover current living expenses. With full FIRE, you don’t need to work at all.

What investment return should I use in the calculator?

A 7% annual return is the standard assumption for US stock market investing, adjusted for inflation. It reflects the long-run historical real return of a broad index like the S&P 500. If you want a more conservative estimate — especially if you’re closer to retirement or hold more bonds — use 5–6%. Avoid using nominal (non-inflation-adjusted) returns without also adjusting your spending estimates, or you’ll overestimate your purchasing power at retirement.

Can I hit Coast FIRE in my 30s?

Yes — it’s one of the most realistic FIRE milestones for people who started investing in their 20s. The math is straightforward: someone who saves $20,000 per year from age 22 to 30 at 7% real returns ends up with roughly $230,000 by their 30th birthday. At that point, they can stop retirement contributions entirely and coast to over $1,750,000 by 65. The earlier you invest aggressively, the lower your Coast number is.

Does Social Security affect my Coast FIRE calculation?

Yes, significantly. Social Security benefits reduce the total portfolio you need to fund retirement, which lowers your FIRE number — and therefore your Coast number. If you expect $20,000 per year from Social Security at 67, you only need your portfolio to cover the remaining gap in retirement spending. Enter your expected Social Security benefit as a reduction to your annual retirement spending estimate in the calculator for a more accurate result.

What’s the risk with Coast FIRE?

The main risk is sequence of returns — if markets perform significantly below average during your compounding years, your portfolio may not reach your target by retirement. Using conservative return assumptions (5–6% rather than 7%) provides a buffer. The other risk is lifestyle creep — if your expenses increase substantially before retirement, your original FIRE number may no longer be enough. Review your numbers every few years as your circumstances change.

More Tools for Your Financial Independence Plan

Coast FIRE is a milestone, not the finish line. Here are more ToolCalcPro calculators to keep your plan on track:

• Use the Correlation Coefficient Calculator to analyze the relationship between variables in your financial data — useful for comparing portfolio performance across different periods.
• Studying probability? The Binomial Distribution Calculator handles statistical calculations that come up in data-driven financial modeling.

You’ve found your number — now you know exactly what you’re working toward. Run different scenarios in the calculator above (earlier retirement, different spending levels, higher or lower returns) to understand how sensitive your Coast FIRE number is to each variable. The answer might surprise you.

Have a question about your specific situation — pension, rental income, or a two-income household? Drop it in the comments below.