Coast FIRE is the point where your invested assets will reach full financial independence by retirement without any further contributions. It is not independence yet: you still need income for today's bills, but you no longer need to save. With $40,000 of spending, a 4% withdrawal rate and 5% real growth, retiring at 65 from age 30, the Coast FIRE number is $181,290 — the amount that grows to $1,000,000 over 35 years.
Spending $40,000 a year at a 4% withdrawal rate needs $1,000,000 invested. The Coast FIRE number for age 30 is $181,290, so you still need $181,290.
Spending $40,000 a year at a 4% withdrawal rate needs $1,000,000 invested. Your Coast FIRE number for age 30 is $181,290, and your portfolio is already $0 past it.
The metaphor is deliberate. A cyclist who stops pedalling does not stop moving; the bike keeps rolling on the momentum already built, slowing only as friction takes its share. Coast FIRE applies that idea to a portfolio. The pedalling is saving and the momentum is the balance already invested. Once the balance is large enough to reach your target by retirement on its own, you can stop pedalling. The word also carries its own warning: you are still moving, but you are no longer adding speed, so the rest of the ride depends on the road ahead rather than on effort.
It is not financial independence. Your spending still needs income, which means work, benefits or some other source. It is not retirement, and it is not a promise that the portfolio arrives on schedule. Returns are not smooth, and a poor decade early in the coasting period can leave you short even when the long-run average holds. Nor is it permission to ignore the portfolio: fees, taxes and asset allocation still matter, and the balance has to be genuinely invested rather than parked in cash that loses ground to inflation every year.
Coasting appeals to people who want to change how they work before they can stop entirely. It fits careers with a demanding early phase and a quieter later one, and it fits anyone whose spending is modest enough that the number arrives while they are still young. It suits less well if your retirement spending is uncertain, if you have dependants, or if health makes future income unreliable. In those cases a larger buffer — a lower withdrawal rate, a few more years of saving, or both — turns a fragile plan into a durable one.
In practice it means you stop adding to your investment accounts and let the existing balance compound to your retirement target. You keep earning to cover living costs, but the pressure to save disappears, which usually changes what kind of work you are willing to take.
There is no fixed age. It depends on your spending, your return assumption and how much you already hold. A larger portfolio or a lower retirement target brings the age down; starting late or spending more pushes it up. The calculator answers it for your own numbers rather than an average.
You can. Some people keep contributing at a lower rate because it shortens the remaining distance and adds a buffer against bad returns. Others redirect the money to a house, a business or time off. Both are consistent with the definition; only the first keeps the original retirement date more secure.
It carries sequence-of-returns risk. The plan assumes the portfolio grows at a steady real rate, and real markets do not. A fall in the first years of coasting hurts more than the same fall later, because there is less time to recover. A conservative return assumption and a lower withdrawal rate are the usual ways to price that risk in.
Lean FIRE means the portfolio already covers a deliberately modest budget, so work is optional now. Coast FIRE means it will cover your budget later without more saving, so work is still required for current costs. One is a current independence on a smaller number; the other is a future independence on the same number.