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Coast FIRE Calculator

Calculate your Coast FIRE number, determine when you can stop contributing to retirement investments, and project your path to financial independence.

Current Financial Information

Currency:
yrs
yrs
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Total invested assets today — 401(k), IRA, brokerage, etc.

$

In today's dollars

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$

What you invest per year now

Investment Assumptions

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S&P 500 ≈ 10% nominal; 7% is conservative

%

U.S. long-run average ≈ 3%

%

The 4% rule is the common default

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%

Annual increase in contributions

What Is Coast FIRE?

Coast FIRE is a milestone on the path to financial independence. You reach it the moment your invested portfolio is large enough that, even if you never contribute another dollar to retirement, compound growth alone will carry it to your full financial-independence number by your target retirement age. You still work to cover today's living expenses — but you no longer have to save for retirement. Your past self has already done that job.

This calculator finds your Coast FIRE number, shows whether you've crossed it, and projects exactly when you will. Pair it with our retirement calculator, compound interest calculator, investment calculator, and inflation calculator to build a complete plan.

How Coast FIRE Works

Front-load the saving

The core idea is to do your heavy retirement saving early, while compounding has the most time to work. Once your balance is big enough, you stop the required saving and let time finish the job.

Compounding does the lifting

Money invested at 30 has 35+ years to grow. At a 5% real return it roughly triples by 65 with no new deposits — which is exactly why a relatively small Coast FIRE number can grow into a full nest egg.

You still work — just freely

Reaching Coast FIRE doesn't mean you stop earning. It means your job only needs to cover current expenses, not fund retirement, opening the door to lower-stress or lower-paid work you enjoy.

The number falls over time

Because there are fewer compounding years left as you age, the Coast FIRE number rises each year. The earlier you hit your target, the smaller the amount you actually need invested today.

Four Ways to Use This Calculator

1

Find Your Number

Enter your age, target retirement age, spending, and assumptions to get the exact amount you'd need invested today to coast to financial independence.

2

Check Your Status

See instantly whether you're already Coast FIRE, on track, or behind — and how big the gap between your current portfolio and your Coast FIRE number is.

3

Project the Timeline

With your current contributions, the calculator shows the year and age you'll cross the Coast FIRE line and can stop saving for retirement.

4

Stress-Test Scenarios

Compare conservative, expected, and optimistic returns side by side, and adjust inflation, withdrawal rate, taxes, and lump sums to see what really moves the number.

How to Calculate Your Coast FIRE Number

The calculation runs in three short steps. First, find your full financial-independence target by dividing annual retirement spending by your safe withdrawal rate — at a 4% rate, $60,000 of spending needs a $1,500,000 portfolio. Second, convert your nominal return into a real return by stripping out inflation, because everything is easier to reason about in today's dollars. Third, discount the FI target back to the present using that real return over the years until retirement.

The result is the amount you'd need invested right now so that compounding alone — zero further contributions — grows it to the full target by retirement. If your current portfolio already meets or exceeds that number, you're Coast FIRE. If not, the calculator shows the gap and how your ongoing contributions close it over time.

Coast FIRE vs Other FIRE Types

Coast FIRE vs Traditional FIRE

Traditional FIRE means you've accumulated your entire nest egg (25–33× expenses) and can stop working entirely. Coast FIRE is the earlier checkpoint where you can stop saving for retirement but still work to cover today's bills. Coast comes years — often decades — before full FIRE.

Coast FIRE vs Barista FIRE

Barista FIRE means working part-time (often for benefits like health insurance) to cover living costs while investments grow untouched. Coast FIRE is similar in spirit but doesn't require part-time work specifically — any income that covers expenses qualifies, full-time or not.

Coast FIRE vs Lean FIRE

Lean FIRE targets a minimalist budget (commonly $25k–$40k/year), reaching full independence on a smaller nest egg. Coast FIRE isn't about budget size — it's about timing. You can be Coast FIRE toward a lean, regular, or fat lifestyle depending on the spending you plug in.

Coast FIRE vs Fat FIRE

Fat FIRE aims for an affluent retirement ($100k+/year), requiring a much larger portfolio. Your Coast FIRE number scales with whatever spending you target, so a Fat FIRE goal simply means a higher Coast FIRE number to hit today.

Compound Growth, the 4% Rule & Inflation

Compound growth is the engine behind Coast FIRE. Each year your returns earn their own returns, so a portfolio left untouched for decades grows far beyond the sum of its parts. This is why the Coast FIRE number can be a fraction of your final target — the missing amount is supplied entirely by compounding over the remaining years.

The 4% rule, derived from the 1998 Trinity Study, estimates that you can withdraw 4% of your starting portfolio each year (adjusted for inflation) with a high probability of not running out over a 30-year retirement. It's the inverse of the 25× rule — 1 ÷ 0.04 = 25 — and it's why dividing spending by the withdrawal rate gives your FI target. For 40+ year retirements, many planners prefer a more conservative 3–3.5% rate.

Inflation quietly reshapes every long-term plan. A dollar today buys more than a dollar in 35 years, so this calculator works in real (inflation-adjusted) terms by default: it converts your nominal return into a real return with the formula Real = ((1 + return) ÷ (1 + inflation)) − 1. Planning in real dollars keeps your spending target and your Coast FIRE number directly comparable.

The Core Coast FIRE Formulas

Every result here reduces to three closed-form equations. Knowing them lets you sanity-check any Coast FIRE claim you read.

Required Portfolio

FI = Annual Spending ÷ Safe Withdrawal Rate

The full nest egg you need at retirement — the inverse of the withdrawal rate (4% → 25× spending).

Real Return

Real = ((1 + Return) ÷ (1 + Inflation)) − 1

Strips inflation out of your nominal return so everything stays in today's dollars.

Coast FIRE Number

Coast = FI ÷ (1 + Real)^(Years to Retirement)

Present value of the FI target — the amount invested today that compounds to FI with no new contributions.

Common Coast FIRE Mistakes

  1. 1

    Using an optimistic return

    Assuming 10%+ nominal returns shrinks your Coast FIRE number on paper but leaves no margin for bad decades. Plan with a conservative 5–7% nominal (≈ 2–4% real) and treat anything above it as a bonus.

  2. 2

    Forgetting inflation

    A nominal target that ignores inflation badly understates what you'll need in 30 years. Always reason in real dollars — this calculator does so by default.

  3. 3

    Ignoring health insurance

    If reaching Coast FIRE means leaving a benefits-providing job, factor health coverage into the spending you plug in. It's one of the largest pre-Medicare costs for early retirees.

  4. 4

    Stopping contributions too soon

    Crossing the Coast FIRE line is based on assumptions that may not hold. A market drop right after you stop saving can push you back below the line — keep a buffer or stay flexible.

  5. 5

    Setting the wrong spending number

    Your entire FI target rides on the annual spending figure. Underestimate it and your Coast FIRE number is too low; pad it for taxes, healthcare, and the lifestyle you actually want.

Built for FIRE planners, early-career savers, and anyone mapping the path to financial independence.

Coast FIRE methodology, the 4% rule, and compound-growth formulas are drawn from public references including the Trinity Study, the SEC's Investor.gov resources, and standard finance literature. See our methodology and editorial policy. Educational only — not financial advice.

Frequently Asked Questions

Coast FIRE is the point at which your invested portfolio is large enough that, without any further retirement contributions, compound growth alone will reach your full financial-independence target by your chosen retirement age. You still work to cover current living costs, but you no longer need to save for retirement — your existing investments coast the rest of the way.

Three steps. First, your financial-independence target = annual retirement spending ÷ safe withdrawal rate (at 4%, that's 25× spending). Second, your real return = ((1 + nominal return) ÷ (1 + inflation)) − 1. Third, the Coast FIRE number = the FI target discounted by the real return over the years remaining until retirement. The result is the amount that, invested today with no new contributions, compounds up to your full target.

Once you hit your Coast FIRE number you can stop contributing to retirement accounts and let your existing investments grow on their own. Many people redirect that freed-up cash toward current lifestyle, take a lower-stress or part-time job, switch careers, or simply work less — confident that compounding is already on track to fund retirement.

Yes — that's the defining feature. By definition, your portfolio is projected to reach your full FI number through compounding alone. In practice, many people keep contributing a little as a buffer against market downturns or weaker-than-assumed returns, since the milestone depends on assumptions that may not hold exactly.

A conservative nominal return of 5–7% (roughly 2–4% real after inflation) is a sensible planning default. The S&P 500 has averaged about 10% nominal over the long run, but planning at that rate leaves no margin for poor decades or sequence-of-returns risk. Lower assumed returns produce a higher, safer Coast FIRE number.

Inflation erodes purchasing power, so a target set in today's dollars buys less in the future. This calculator handles it by working in real terms: it converts your nominal return into a real return using Real = ((1 + return) ÷ (1 + inflation)) − 1, keeping your spending goal and Coast FIRE number directly comparable in today's money.

The 4% rule, from the 1998 Trinity Study, suggests you can withdraw 4% of your starting portfolio in the first year of retirement (then adjust for inflation annually) with a high probability of not running out over 30 years. It implies a portfolio of 25× annual spending. For 40+ year retirements, a more conservative 3–3.5% rate is often used.

Neither is strictly better — they're different milestones. Coast FIRE comes far earlier and frees you from the pressure to save for retirement, while still requiring income to cover current expenses. Traditional FIRE means you've saved enough to stop working entirely. Coast FIRE is a flexible middle ground many people reach years or decades before full FIRE.

It's an accurate model of the standard Coast FIRE math, but its output is only as good as your assumptions. Real markets are volatile, returns vary year to year, inflation shifts, and life changes spending. Treat the results as a well-grounded estimate and planning guide, run several scenarios, and revisit them annually — not as a guarantee.

Absolutely — most people do. Coast FIRE simply removes the requirement to save for retirement; it doesn't require you to stop earning. Your job only needs to cover present-day expenses, which opens the door to more enjoyable, lower-paid, part-time, or entrepreneurial work while your investments keep compounding toward financial independence.

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