Is Coast FIRE Risky? Sequence of Returns and Coasting
Coast FIRE front-loads your savings, then lets growth do the rest - which means the order returns arrive in matters more than their average. Here's what that risk actually looks like.
Every coast plan makes the same bet: stop adding new money early, and let compounding finish the job by the time you actually retire. That bet has a specific failure mode most calculators never show you - it isn’t about whether markets go up over long periods (they almost always have). It’s about when the bad years land relative to your stop-saving date.
Two identical averages, two different outcomes
Imagine two savers who coast at the same age with the same portfolio, and over the following 25 years the market delivers exactly the same average real return for both of them. They can still end up decades apart. If saver A’s bad years land early - right after the last paycheck stops going in - a smaller portfolio absorbs the damage and has less time to recover before withdrawals begin. If saver B’s bad years land late, the portfolio has already grown past the danger zone. Same average, opposite outcome. That gap is sequence-of-returns risk, and it’s the entire reason a coast number is better expressed as a probability than a single age.
This is why Coastward never resamples single years independently. Real crashes cluster with their aftermath - 1929, 1973–74, 2000–02, and 2008 each opened a multi-year stretch, not one bad roll of the dice. The simulator draws multi-year blocks of real history instead, so a crash keeps the recovery (or the lack of one) that actually followed it. More on the block bootstrap →
Run this scenario yourself
Same idea, your inputs: watch the fan chart widen around your own coast age and see how many of 10,000 historical sequences actually held up.
How much does the stop-saving decade matter?
Below is a representative example: one coast scenario ($150k net worth, $45k spend, retiring by 60), run at three different expected real return assumptions. The coast age barely moves - but the historical success rate, measured across the same block bootstrap the tool runs live, moves a lot more than a single “expected return” line would suggest.
| Assumed real return | Coast age | Historical success rate |
|---|---|---|
| 3% (conservative) | 38 | 61% |
| 5% (Coastward default) | 35 | 78% |
| 7% (US historical mean) | 32 | 84% |
Illustrative figures for the scenario above - not a universal table; your own success rate depends on your income, spend, and allocation. Why we default below the historical mean →
What a bad first decade actually costs you
In this illustrative scenario, run through the same block bootstrap the tool runs live, this exact coast plan - stop saving at 35, retire by 60 - survived in 78% of 10,000 replays of real market history. The unlucky quarter mostly shares one trait: a below-average stretch in the first five to eight years after coasting starts, before the portfolio had size on its side. That’s the honest shape of the risk - not “coasting is dangerous,” but “the first stretch after you stop saving carries more weight than the decades after it.” (Your own plan’s numbers will differ - try it in the tool.)
What actually reduces the risk
- A longer runway between your coast age and your retire-by age gives bad early sequences more time to recover.
- A lower assumed return narrows the gap between the straight-line answer and the historical one - it’s a more honest starting point, not a fix on its own.
- The barista option (a small part-time contribution instead of zero) measurably shrinks the failure tail, because it’s new money buying at exactly the depressed prices a bad sequence produces.
The honest range
Coast FIRE isn’t riskier than working-and-saving straight through to full FI - it just concentrates the risk into a specific window: the years right after you stop adding new money. Seeing that window as a probability, not a single age, is the whole point of running the simulation instead of a spreadsheet. If you’re still fuzzy on the mechanics, start with what Coast FIRE actually is; if you want the machinery behind these numbers, here’s how Coastward works.
See your own sequence-risk exposure
Plug in your numbers and watch the deterministic answer, then the probability band around it - the same view used throughout this piece.
Frequently asked
Is Coast FIRE riskier than a normal retirement plan?
Not inherently riskier - but the risk shows up differently: coasting means growth alone has to carry the last stretch, so the plan is more exposed to the specific sequence of returns it draws after you stop contributing.
What is sequence-of-returns risk?
The risk that WHEN good and bad years happen matters as much as their average - a crash right after you stop saving hits a plan differently than the same crash a decade earlier, even with identical average returns.
Does a market crash right after I stop saving ruin my plan?
Not automatically - it depends on how much runway you have before you need the money. The historical block-bootstrap in the tool shows how often plans like yours actually recovered.
What return assumption should I use for Coast FIRE?
Something below the long US historical average, which was an unusually lucky stretch. Coastward defaults to 5% real, below the ~7% historical mean, and lets you dial it down further.