Coast FIRE Calculator

Find the portfolio value that lets compound growth alone carry you to financial independence — no more contributions required.

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What Is Coast FIRE?

Coast FIRE (sometimes written Coast FI) is the point on your financial independence journey where your invested assets are large enough that, even if you never add another dollar, compound growth alone will carry your portfolio to a full FIRE number by your target retirement age. It is the "stop-saving" milestone — the moment aggressive saving becomes optional rather than mandatory.

This free Coast FIRE calculator computes your personal Coast FIRE number from four inputs: the FIRE number you want to retire on, your expected real (inflation-adjusted) return, your current age, and the age you plan to retire. The math is straightforward, but the implications are profound: people who hit Coast FIRE in their 30s or 40s can step off the hamster wheel, switch to lower-paying work they actually enjoy, or take extended career breaks — all without derailing retirement.

Coast FIRE vs. Regular FIRE, Lean FIRE, and Barista FIRE

Regular FIRE means hitting your full FIRE number — typically 25× annual expenses if you use the classic 4% rule — so that portfolio withdrawals can cover your lifestyle indefinitely. Lean FIRE is the same idea with a stripped-down budget (often under $40k/year in expenses). Barista FIRE sits between Coast FIRE and full FIRE: you have enough invested that a part-time job covers the remainder of your current expenses while investments continue to compound untouched. Coast FIRE is the earliest of these milestones because it only requires enough invested today to compound into your FIRE number by a future date — you still need income to cover current expenses along the way. See our FIRE dashboard and financial independence insights for broader comparisons.

How to Calculate Your Coast FIRE Number

The Coast FIRE formula is a rearranged future-value equation:

Coast FIRE Number = FIRE Number / (1 + r)^n

Where r is your expected annual real return (after inflation) and n is the number of years until you plan to retire. For example, if you want $1,625,000 at age 65 (a 4% withdrawal rate on $65,000/year in expenses), you're currently 30, and you expect a 7% real return over the next 35 years, your Coast FIRE number is $1,625,000 / (1.07)^35 ≈ $152,300. Invest that much today, never add another dollar, and compound growth at 7% real for 35 years carries you to your full FIRE number.

Always use real returns (typically 5–7% for a diversified stock portfolio) rather than nominal returns so the result is in today's dollars and directly comparable to today's expenses. The farther away your retirement, the lower your Coast FIRE number — time is the single most powerful variable in the equation.

How to Use This Coast FIRE Calculator

1. Enter your current age and the age you plan to retire. The gap between them drives everything.

2. Enter your current net worth — invested assets that will actually compound (brokerage, 401(k), IRA, Roth IRA, HSA). Exclude your primary residence's equity unless you plan to sell and invest it.

3. Enter your expected annual expenses in retirement in today's dollars. The calculator converts this into a FIRE number using your chosen withdrawal rate.

4. Set your withdrawal rate. 4% is the traditional Trinity Study baseline; more conservative planners use 3.5% or even 3%.

5. Set your real return. 7% is a common historical baseline for U.S. equities after inflation; use 5% for a more conservative or bond-heavy portfolio.

6. Read the result. If your current net worth is already above the Coast FIRE number, you've hit the milestone. If not, the calculator shows the gap and a chart comparing stopping contributions today versus continuing to save.

Why Coast FIRE Matters

Reaching Coast FIRE fundamentally changes your relationship with work. Because future retirement is already funded by math, every dollar you earn from that point forward covers only current expenses. That opens doors: switching to a lower-stress job, going part-time, starting a business, taking a sabbatical, or moving somewhere with a lower cost of living. It also provides a psychological runway — the knowledge that if your career blows up tomorrow, your retirement isn't in jeopardy, only your timeline to full FIRE is.

Limitations and Assumptions

The Coast FIRE formula assumes a smooth, constant rate of return. Real markets don't cooperate: a major bear market in the first decade of your coast period can permanently lower the trajectory (the "sequence of returns risk" that haunts retirement planning). It also assumes your expense estimate is accurate across decades, which is hard to pin down given healthcare inflation, lifestyle creep, and unpredictable life events. Build in a safety margin: aim for 120–150% of your calculated Coast FIRE number before actually stopping contributions, or continue contributing at a reduced rate. This calculator is an educational tool, not personalized financial advice.

Coast FIRE FAQ

Is Coast FIRE realistic for the average earner?

Yes, especially for people who start in their 20s. The Coast FIRE number drops sharply with time: at 7% real, $100,000 invested at age 25 becomes roughly $1,500,000 by age 65 with zero additional contributions. The earlier you front-load savings, the smaller the total contributions needed.

What return should I use for Coast FIRE?

Use a real (inflation-adjusted) return. Historical U.S. stock returns run roughly 6.5–7% real over long periods. A conservative planner uses 5%; an aggressive one uses 7%. Avoid nominal returns — they make today's dollars and tomorrow's dollars incomparable.

Does Coast FIRE include Social Security?

By default, no. Social Security is a separate income stream that reduces the portfolio withdrawals you'll actually need. If you want to factor it in, subtract its annual equivalent from your retirement expenses before computing your FIRE number.

How is Coast FIRE different from Barista FIRE?

Coast FIRE means you've saved enough that compound growth alone will reach your FIRE number by retirement — but you still need to earn enough to cover today's expenses. Barista FIRE means you've saved enough that a part-time or low-paying job can cover current expenses, with retirement already fully funded by the invested portfolio.

Can I keep contributing after reaching Coast FIRE?

Absolutely. Many people continue contributing because it pulls their FIRE date closer or lets them retire with a larger cushion. Coast FIRE is a permission slip to stop, not a command — the chart above shows exactly how much faster full FIRE arrives if you keep saving.