Maximizing Risk-Adjusted Returns
The point where your existing savings will carry you through retirement on their own
Coast FI is short for Coast Financial Independence. The FI half is the same financial independence the FIRE movement chases, a portfolio large enough to fund your life without working. The Coast half is what makes it different: you stop pushing and let the balance carry itself the rest of the way.
Concretely, it is the point where your invested balance is large enough that, if you never contributed another dollar, compounding alone would grow it into a full retirement portfolio by the time you need it. You are not retired. You still work and still cover your living costs. What you no longer have to do is save for retirement.
A 35 year old who wants $60,000 a year at 65, drawing at 4.7%, needs $1,276,596. At a 6% real return over 30 years, that $1,276,596 traces back to roughly $222,268 today. Cross $222,268 and the remaining $1,054,328 is compounding rather than contributions.
The younger you are when you cross, the more extreme that split gets. Take the same $1,276,596 target, but reach it from age 24 instead of 35. Forty one years of compounding means the Coast number is only about $117,088. Below, the lower band is that $117,088 sitting in the account. It never grows, because nothing more is ever added. Everything above it is compounding.
A single 6% real return applied for 41 years, with no further contributions after age 24. The growth band overtakes the contribution band at age 36 and never looks back. Reaching six figures early is hard, and most people cross the Coast line later than this. That is the point of the chart rather than an argument against it: every year earlier you cross, a larger share of your retirement gets produced by money you already have instead of money you have yet to earn.
Most people who calculate a Coast number keep saving anyway. The value is in what it tells you: past the Coast line, your retirement is no longer hostage to your next paycheck. That reframes a layoff, a sabbatical, a lower paying job you would rather do, or a year off with family. The number converts an abstract worry into a date.
Everything here is in today's dollars. Enter a return after inflation and the answer stays comparable to what money buys now.
This calculator is an educational illustration, not financial advice or a projection of results. It applies one fixed return every year, which no real portfolio delivers. It ignores taxes, fees, Social Security, pensions, and any spending change in retirement. Talk to a qualified adviser about your own situation.
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Both start from the same arithmetic. They differ in what they ask of you and how badly they fail when the assumptions turn out wrong.
| Coast FI | Full FIRE | |
|---|---|---|
| The goal | Stop saving for retirement | Stop working for income |
| Savings rate needed | High for a shorter stretch, then optional | Very high, sustained for many years |
| Target size | A fraction of the FI number, discounted by time | The full FI number |
| Typical timeline | Reachable in your thirties or forties | Usually a decade or more of maximum saving |
| Main risk | Returns come in below assumption over decades | A bad decade lands right at the start of withdrawals |
| Recovery from a bad outcome | Resume contributions, or work a little longer | Return to work after years out of the market |
| Income still required | Yes, to cover living costs until retirement | No, the portfolio covers everything |
Coast FI keeps a working income between you and your portfolio for years, sometimes decades. That income is the buffer. If a bear market arrives at 45 and you are Coasting, you have twenty years and a paycheck to absorb it. If it arrives in year two of full FIRE, you are selling depressed assets to eat, which is the failure mode that sinks otherwise sound withdrawal plans.
You are still working. Coast FI does not buy freedom from employment, it buys freedom from the savings requirement, and those are different things. For people whose real complaint is the job itself rather than the saving, Coasting solves the smaller problem. It just solves it far sooner, and it leaves the door to full FIRE open, since anything you keep contributing after the Coast point pulls that date closer.
Every input in the coast formula is something you can act on this year. Time is not. The years between now and retirement are fixed the moment you decide to start, and because the formula compounds a return over that stretch, time does more work than any other variable in it.
The table below holds everything else constant, a $1,276,596 target and a 6% real return, and moves only the starting age.
| Starting age | Years to compound | Coast number needed |
|---|---|---|
| 25 | 40 | $124,113 |
| 30 | 35 | $166,092 |
| 35 | 30 | $222,268 |
| 40 | 25 | $297,445 |
| 45 | 20 | $398,049 |
| 50 | 15 | $532,679 |
| 55 | 10 | $712,845 |
Waiting from 25 to 35 to reach the same coast number costs $98,155, not because you spent it, but because you handed ten years of compounding back. Wait until 45 and the number needed more than triples what a 25 year old would have needed. The gap is not linear. Each decade of delay costs more than the one before it, because the years being given up are the ones closest to today, which are also the ones with the longest remaining runway to compound.
A dollar Coasted at 25 is worth roughly three dollars saved at 45, purely from the extra time it has to compound. That makes an early dollar categorically more valuable than a late one, not just a nice-to-have. If you are early in your career, this is the argument for front-loading contributions even at the expense of other goals: the same effort produces a disproportionately larger result the sooner it starts.
If you are past 35 or 40, the table is not a verdict, it is a different lever. You cannot buy back the years, but you can raise the contribution, extend the timeline by a few years, or accept a somewhat lower target. Any of those closes the same gap that time would otherwise have closed for you.
Coast FI is a permission, not an instruction. Hitting the number means you are allowed to stop saving. Dropping to zero on the day you cross is usually the wrong call.
The step from a maximum contribution to a moderate one changes your monthly budget substantially. The step from moderate to zero changes your retirement outcome far more than it changes your lifestyle. A common landing spot is contributing enough to capture the full match and stay in a favorable tax position, then directing what you were saving toward whatever the Coast number was meant to fund: shorter hours, a career change, a sabbatical, or time you will not get back.
Your Coast number is anchored to a spending figure. That figure is the one input guaranteed to change, and it changes in the direction that makes the number bigger.
Suppose $60,000 a year covers your life today, so at a 4.7% withdrawal rate your FI number is $1,276,596. At 3% inflation, the same life costs about $61,800 next year, and the FI number becomes $1,314,894. Your Coast number moves with it. Nothing about your behavior changed. The goalposts did.
Once a year, pick a date and redo four inputs: your actual balance, what your life actually costs now, your remaining years to retirement, and whether your return assumption still looks reasonable. Most years the answer is that you are still fine. The check is cheap, and the years when it says otherwise are exactly the years you want to know early, while you still have time to respond with a small adjustment rather than a large one.
Leave your email and we will send one message a year from now, reminding you to come back and recheck your number, then the same reminder every year after that. That is the only thing this signs you up for. It is not the DMS newsletter, nothing else gets sent in between, and you can unsubscribe from the link in any of those emails at any time.
Every other input is something you can observe. The return is a forecast, it is compounded across decades, and small changes to it move the Coast number more than anything else you can adjust.
Take a $1,276,596 FI number 30 years out. At 7% real, the Coast number today is about $167,703. At 6% it is about $222,268. At 5% it is about $295,376. One percentage point of optimism cuts roughly a quarter off what you think you need. Two points cuts it nearly in half. That is not a rounding error, it is the difference between Coasting and believing you are Coasting.
The Coast formula applies one return every year. Markets do not work that way, and the gap between the smooth line and a real path is where Coast plans quietly come apart.
Below, both portfolios start at $250,000 and both average the same annual return over 30 years. One compounds evenly. The other takes a 45% decline early and then recovers at a higher rate to finish with the same average. The arithmetic is identical. The ending balances are not.
Same average annual return, different order. A large decline early removes capital that would have compounded for the entire remaining period, and no later recovery rate fully replaces it.
While you are still contributing, a decline is partly an opportunity, since every contribution buys in cheaper. A coaster has given that up. With no new money going in, a deep drawdown is simply lost compounding, and the only remaining tools are more time or resumed contributions.
A Coast plan is a bet on a compounding rate holding up over decades, so anything that reduces the depth of the worst declines is directly protecting that bet. Tactical strategies of the kind published on this site are built to shift toward defensive assets when trend and momentum signals deteriorate, with the aim of participating in less of the largest declines. That is a design goal rather than a guarantee, and no approach avoids losses entirely. Any strategy you adopt should be one whose rules and historical behavior you have examined yourself, including its bad periods. The general point stands regardless of what you choose: for someone Coasting, drawdown control is not a stylistic preference, it is the part of the plan that protects the assumption everything else rests on.