Coast FIRE Calculator

What coasting actually means

Coast FIRE is the point at which the money you have already saved will compound to your retirement target on its own, without a single further contribution. It is not retirement. You still need income to live on. What changes is that you no longer need to save.

For a lot of people that is the more useful milestone, because it is reached far earlier than financial independence and it unlocks real choices: a lower-paid job you prefer, fewer hours, a career change, or simply spending what you earn without guilt.

The arithmetic is a rearrangement of compound growth. Given what you have, the return you expect and the target you want, the tool solves for how long the existing balance needs to compound.

Why the return assumption should be a real one

This calculator asks for a real return, meaning after inflation, and expects your target to be expressed in today's money. Mixing the two, a nominal return against a target in today's money, is the most common error in retirement arithmetic and it flatters the result substantially.

Around 5% to 7% real is the range most people use for a globally diversified equity portfolio, based on long-run history. It is an assumption, not a promise, and the difference between 5% and 7% over thirty years is enormous, which is worth seeing for yourself by changing the input.

The limitation worth taking seriously

Coasting assumes returns arrive roughly on schedule. They will not. A poor first decade pushes the coast point out, and you will not know that has happened until years later, by which time you have already stopped contributing.

Treat the coast point as a checkpoint you re-examine every few years rather than a finish line you cross once. If markets disappoint early, the honest response is to resume contributing rather than to assume it averages out.

The formula, written out

There is only one equation behind this. Your coast number is the target divided by growth over the years remaining: target / (1 + r)^n, where r is the real return and n is the years until you retire.

Take a target of $1.5 million, a retirement age of 65 and a 7% real return. At 40 you have 25 years left, so the divisor is 1.07^25, which is 5.43. That makes the coast number $276,400. Reach that balance at 40 and, on those assumptions, you never have to save another cent.

Everything the calculator does is that division, run for every age until your balance overtakes the number.

How much the return assumption moves the answer

The single input that changes the result most is the one nobody can know. Hold everything else fixed, a $1.5 million target and 25 years to run, and vary only the real return.

At 7% the coast number is $276,400. At 5% it is $442,900, roughly 60% more capital for the same outcome. At 9% it falls to $174,000. Two percentage points either side of a common assumption changes the requirement by more than half.

That range is the honest answer to 'what number do I need'. Anyone quoting a single figure without stating the return behind it is quoting an opinion. Run the tool at 5% as well as your preferred number, and treat the higher figure as the one to plan around.

Coast FIRE, Barista FIRE and regular FIRE

The three get used interchangeably and mean quite different things. Regular FIRE means the portfolio covers your living costs now, which is usually framed as 25 times annual spending. You can stop working entirely.

Coast FIRE means you can stop saving but not stop working. The balance grows into the target on its own while your job covers day-to-day costs. It arrives years, often more than a decade, before regular FIRE.

Barista FIRE sits between them. The portfolio covers part of your costs and part-time work covers the rest, frequently chosen for health insurance in the US rather than for the income. It needs more capital than coasting and less than full independence.

The practical difference is what each one buys you. Coast FIRE buys the freedom to take a worse-paying job you prefer. Barista FIRE buys shorter hours. Regular FIRE buys the option to stop.

Common questions

What is the difference between Coast FIRE and regular FIRE?

FIRE means having enough to live on the portfolio now. Coast FIRE means having enough that it will grow into that amount by your retirement date without further saving. Coast comes much earlier and still requires you to cover your living costs from work in the meantime.

Should I use a nominal or real return?

A real return, and a target in today's money. Otherwise you are comparing a future number against present-day costs, which overstates how close you are.

What happens if returns are worse than assumed?

The coast point moves later and you will need to contribute again. That is why it is worth rerunning the number every couple of years rather than treating one calculation as settled.

Does this account for tax on withdrawals?

No. Set your target high enough to cover the tax you expect to pay, or treat the output as a pre-tax figure.

Should I include the equity in my house?

Only if you genuinely intend to sell it and live on the proceeds. A home you plan to keep living in produces no retirement income, so counting it inflates the balance and brings your coast point forward on paper without changing anything real.

Do employer contributions count?

Yes, as part of the balance and as part of the monthly contribution while you are still saving. Note that most employer matches stop when you stop contributing, so reaching your coast number and then cutting your own contributions to zero can cost you the match as well.

What if I want to retire before 65?

Lower the retirement age and the coast number rises sharply, because you are removing compounding years from the denominator. Retiring at 55 instead of 65 on a $1.5M target at 7% real raises the coast number at age 40 from $276,400 to $543,700.

What happens if I keep contributing past the coast point?

You either retire earlier than planned or retire on more than the target. Coasting is a floor rather than an instruction. A lot of people pass their coast number and carry on saving anyway, which is a perfectly reasonable way to build a margin against the return assumption being wrong.

How often should I recheck this?

Annually is enough, and after any large market move. The number moves when your balance moves and when the years remaining shrink, so it is never settled. Rechecking is the whole defence against a poor early decade going unnoticed.

Is Coast FIRE the same as being financially independent?

No. Financial independence means the portfolio covers your costs today. Coast FIRE means it will cover them by your retirement date without further saving. You still need earned income in the meantime, which is the part that gets lost when the terms are used loosely.