Coast FIRE Calculator
Coast FIRE (or Coast FI) is the point where the money you have already invested will grow, with no further contributions, into your full FIRE number by the age you retire. From then on you only need to earn enough to cover today's expenses — saving for retirement becomes optional.
Coast FIRE (or Coast FI) is the point at which your retirement savings, left alone to grow, will reach your full FIRE number by the age you plan to retire. Once you hit it, you no longer need to save for retirement — you only need to earn enough to cover today’s bills. This calculator finds your Coast FIRE number, your progress toward it, the age you will reach it at your current savings rate, and what you would need to invest each month to get there sooner.
Examples
Age 30, $25,000 saved, $500 a month, 7% real return
FIRE target = $1,000,000 ($40,000 / 4%). Over 35 years at 7% real, today's Coast FIRE number is $93,663, so $25,000 is 26.7% of the way there. Investing $500 a month, the balance catches up with the rising Coast number at age 53; from then on, growth alone is projected to reach $1,000,000 by 65.
Age 40, retire at 65, $60,000 expenses, 6% real return
FIRE target = $1,500,000. With 25 years of compounding at 6% the growth factor is 4.29, so the Coast FIRE number is $349,498. A later start and a lower return both raise the bar: Coast FI is easiest to reach when time is on your side.
Low-return case: same plan at 4% real
Cut the real return from 7% to 4% and today's Coast FIRE number rises from $93,663 to $253,415 — 2.7 times as much. With $25,000 saved and $500 a month, Coast FIRE is not reached before 65. This is why the sensitivity table matters more than any single figure.
Already past the Coast point: age 35, $300,000 saved
Planning for a 25-year horizon on $50,000 a year at a cautious 3.5% withdrawal rate gives a FIRE target of $1,428,571 and a Coast FIRE number of $263,213. $300,000 is 114% of that, so this saver has already reached Coast FIRE: with no further contributions it is projected to grow to $1,628,230 by 60.
How much a month to coast by 35?
Starting from $25,000 at 30, reaching Coast FIRE by 35 takes $1,352.66 a month at 7% real. At 35 the Coast number has grown to $131,367, and the balance meets it exactly — after that, contributions are optional.
Coast FIRE vs Lean, Barista, Fat and regular FIRE
| Type | What it means | Who it suits | Calculator |
|---|---|---|---|
| Coast FIRE | Enough invested that growth alone reaches your FIRE number by retirement. You stop saving for retirement but keep working to pay current bills. | People who saved early and want lower-pressure work or more time now | Coast FIRE Calculator |
| Lean FIRE | Full financial independence on a deliberately small budget, often well under the median household’s spending. | Frugal savers who want out of full-time work as soon as possible | FIRE Number Calculator |
| Barista FIRE | Portfolio withdrawals plus part-time income cover expenses now. You stop full-time work and start drawing down. | People happy to keep some paid work, often for benefits or structure | Barista FIRE Calculator |
| Fat FIRE | Full independence with a generous budget — larger home, travel, more cushion. | High earners who want to retire without cutting their lifestyle | FIRE Number Calculator |
| Regular FIRE | A portfolio big enough that a safe withdrawal covers all of your expenses for good. | Anyone aiming to make work fully optional | FIRE Number Calculator |
Frequently Asked Questions
Do I still need to save once I hit Coast FIRE?
Not for retirement, if the assumptions hold: your current savings are projected to grow to your FIRE number by your retirement age with no further contributions. You still need income to cover today's expenses, and many people keep saving something as a buffer against lower returns than assumed.
How is Coast FIRE different from full FIRE?
Full FIRE is the portfolio size at which a safe withdrawal covers your annual expenses indefinitely — you can stop working entirely. Coast FIRE is a smaller intermediate milestone: you can stop *contributing* and let compounding do the rest, but you still need income to cover today's expenses (a "coast job" or any income source).
Is a 7% real return realistic?
For an all-stock US portfolio over many decades, roughly — long-run US stock returns after inflation have been in the 6–7% range, but with long stretches far below that. A balanced stock and bond portfolio has historically returned less, closer to 4–5% real. If you are unsure, plan with 5–6% and check the sensitivity table: at 5% the Coast number for a 35-year horizon is almost twice the 7% figure.
What withdrawal rate should I use for a 40+ year retirement?
Something below 4%. The 4% rule was tested on 30-year retirements; for retirements of 40 years or more, many planners use 3.25–3.5%. A lower rate raises your FIRE target — at 3.5%, $40,000 a year needs about $1,142,857 instead of $1,000,000 — and the Coast number rises in proportion.
What discount rate / return should I use?
Use a real (inflation-adjusted) return. Historically, US equities have returned about 7% real (10% nominal minus ~3% inflation). Bond-heavy portfolios are lower (4-5% real). Mixing real and nominal numbers will overstate your progress.
How is Coast FIRE different from Barista FIRE?
Coast FIRE means you stop saving but do not touch the portfolio: earned income still pays all of today’s expenses while your investments grow to the full target. Barista FIRE means you start withdrawing now, with part-time income covering the gap between withdrawals and spending. Coast FIRE needs a smaller portfolio; Barista FIRE needs less work.
What if markets drop right after I stop contributing?
Your Coast date moves later. A fall early on hurts most because the portfolio is still small and has to recover before it can compound toward the target. The usual responses are to keep contributing for a few more years as a margin of safety, to plan with a lower return than history suggests, and to recheck your progress each year rather than treating the Coast date as fixed.
Do 401(k)/IRA balances and home equity count?
Retirement accounts count; home equity usually does not. 401(k), 403(b), IRA, Roth and taxable brokerage accounts invested for retirement belong in current savings. Home equity only counts if you plan to sell or downsize and invest the proceeds, and cash held for emergencies or near-term goals should be left out.
What if I'm already past Coast FIRE?
You're free to redirect savings elsewhere — paying down a mortgage, taking a sabbatical, switching to a lower-paying but more meaningful job. The math says compounding alone will hit your retirement target; new contributions accelerate to full FIRE rather than being required for it.
Does this account for inflation?
Yes — by convention, you enter expenses in today's dollars and use a real return. The 4% rule already adjusts withdrawals for inflation each year, and the Coast FIRE math inherits that framing. Don't mix in nominal returns or inflated future expense projections.
Related Information
Coast FI changes the question from “how much more do I need to save?” to “how long until I can stop?” Two numbers drive the answer. The first is time: the Coast number falls the further you are from retirement, so the same savings go much further at 25 than at 45. The second is your contribution rate: the Coast number rises every year at your expected return, and only new money lets your balance close the gap. That is why the Coast age moves sharply with the monthly contribution but barely with small changes in current savings. Treat the result as a range rather than a date. A return 1 percentage point lower than planned can add years to the Coast date, and the years right after you stop contributing carry the most risk. Many people pick a Coast target with a margin — coasting at 110–125% of the Coast number, or keeping a smaller contribution going — and switch to lower-paid or part-time work only once the balance has held up through a few years of market swings.
Sources
- Bengen, W. P. (1994). "Determining Withdrawal Rates Using Historical Data." — Journal of Financial Planning
- Cooley, P. L., Hubbard, C. M., Walz, D. T. (1998). "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable." (the Trinity study) — AAII Journal
- Damodaran, A. Historical Returns on Stocks, Bonds and Bills: 1928–present — NYU Stern School of Business
Result
$93,663
- Coast FIRE number
- $93,663
- Full FIRE target
- $1,000,000
- Progress to Coast FIRE
- 26.7%
- Coast FIRE age
- Age 53 (in 23 years)
Related Calculators
Quick Tips
- •Front-load savings: money invested in your twenties has the most years to compound, so a few years of high saving can reach Coast FIRE.
- •Re-run the numbers each year with your actual balance instead of trusting a single projection.
- •Plan with a lower return than history suggests; the sensitivity table shows the cost of being wrong.
- •Keep an emergency fund outside the portfolio so a job gap does not force early withdrawals.