Coast FIRE is the point where the money you have already invested is projected to grow, on its own, into a full retirement nest egg by the time you reach a normal retirement age, even if you never contribute another dollar. You are not financially independent yet. You have just taken savings off the table as a requirement.
The name captures the idea well: like a cyclist who stops pedaling on a downhill stretch, you can ease off the aggressive saving and let momentum, compound interest in this case, carry you the rest of the way. What you cannot do is stop earning entirely. You still need income to cover today's living costs. You have only solved for retirement.
How Coast FIRE is different from regular FIRE
Regular FIRE has one finish line: the day your invested assets can fully replace your income, at which point you can walk away from work entirely. Coast FIRE has two separate questions with two separate answers. Have you saved enough for retirement to take care of itself? And, separately, can your current income cover your current expenses? Once the first question is answered yes, the second one gets a lot more flexible.
That flexibility is the whole appeal. Reaching Coast FIRE means you can switch to a lower-paying job you actually enjoy, drop to part-time, take a year off between careers, or simply stop stressing about every raise and promotion, all without derailing your retirement date. Your investments keep compounding in the background while your income only needs to cover the present.
The math: finding your coast number
Your coast number is smaller than your full FIRE number, and how much smaller depends entirely on how many years you have left until retirement. The formula: coast number = FIRE number ÷ (1 + real annual return) raised to the power of years until retirement.
Say your FIRE number is $1,000,000, you are 30, plan to retire at 65 (35 years away), and expect a 7% annual return after inflation. Your coast number today is roughly $1,000,000 ÷ 1.07^35, which works out to about $107,000. Save that much, invest it in something reasonable, and 35 years of compounding does the rest.
Notice how sensitive that number is to your timeline. The same $1,000,000 target needs a coast number of roughly $258,000 if you are 45 with only 20 years left, since compound growth has far less time to work. The earlier you calculate from, the smaller the number, and the more of your working life you get to spend without a savings mandate hanging over every paycheck. Try the Coast FIRE calculator with your own numbers to see where you stand today.
Why people aim for Coast FIRE instead of full FIRE
Full FIRE, especially lean FIRE, sometimes means years of hard cost-cutting for a payoff that is a decade or more away. Coast FIRE offers a nearer-term reward: once you clear the coast number, the pressure comes off immediately, even though the actual retirement date has not changed. For a lot of people, trading a bit more career flexibility today for the same retirement timeline is worth more than shaving a few years off the end.
It is also a natural stopping point for people who front-loaded their savings early in their career, through a first job with a high salary, an inheritance, or just aggressive saving in their twenties, and would rather ease up than keep grinding at the same pace for another two decades.
Where people get Coast FIRE wrong
The most common mistake is treating Coast FIRE as the finish line instead of a checkpoint. You still have decades of expenses to cover between now and retirement, and if your income drops without a clear plan for meeting them, you can end up dipping into the very investments you were trying to leave untouched.
The second mistake is picking assumptions that are too generous. A 10% expected return with no allowance for inflation makes any coast number look smaller than it really is. Sticking with a moderate real return, most FIRE calculators default to somewhere around 5% to 7%, gives you a coast number you can actually trust.
The third is forgetting about benefits. If coasting means leaving a job with employer-sponsored health insurance for a lower-paying one without it, run the numbers on that cost too. It has nothing to do with your investment math, but it can undo the flexibility Coast FIRE was supposed to buy you.
Calculate your own coast number
Enter your age, savings, and target retirement age to see exactly how much you need invested today to coast the rest of the way.
Open the Coast FIRE calculatorFrequently asked questions
Is Coast FIRE the same as Barista FIRE?
They are related but not identical. Barista FIRE usually means you have saved enough to cover most, but not all, of your expenses, so you take a lower-stress job, often for the health benefits, to cover the gap. Coast FIRE is about retirement savings specifically: your job still needs to cover all of your current living costs, but you no longer need to add to your retirement investments.
What age can I expect to reach Coast FIRE?
It depends entirely on your savings rate and starting income, not a fixed age. Someone who saves aggressively in their twenties might reach it by their early thirties. Someone who starts saving seriously at 35 might reach it in their late forties. Run your own numbers with a Coast FIRE calculator rather than relying on an average.
Do I need to keep investing after reaching Coast FIRE?
No, that is the point: your existing balance is projected to reach your FIRE number on its own. That said, many people who reach coast keep contributing a smaller amount anyway, since it shortens the timeline further or builds in a buffer against a weak market.
How does the safe withdrawal rate affect my coast number?
Your safe withdrawal rate determines your FIRE number in the first place (FIRE number = annual expenses ÷ safe withdrawal rate), and your coast number is calculated as a percentage of that FIRE number. A lower, more conservative withdrawal rate raises your FIRE number, which raises your coast number too.
What return rate should I use to calculate my coast number?
Use a real return, your expected investment return minus expected inflation, rather than a raw historical average. Most calculators, including ours, default to somewhere between 5% and 7%, which reflects long-run stock market performance after inflation.