Coast FIRE is the amount that, left alone, grows to your retirement goal without another dollar added. See your coast number and whether you have hit it.
How this is calculated Embed on your siteUpdated October 2026
Coast FIRE is the point where the money you have already invested will grow into a full retirement fund on its own, with no new contributions. Once you reach it, you still need to earn enough to pay today's bills, but you no longer need to save for retirement. That is the appeal: you can take a lower-paying job, work part time, or take a long break without derailing your plan.
With the default inputs, a 30-year-old who wants $60,000 a year at 65 needs a $1,500,000 nest egg at a 4% withdrawal rate. At a 5% real return, $271,935 invested today grows to that amount in 35 years. They have $100,000, so they are $171,935 short of coasting.
There are two steps. First, find your full FIRE number: annual retirement spending divided by your withdrawal rate. Second, discount it back to today at your expected real return:
Coast number = FIRE number ÷ (1 + real return)years until retirement
Because everything is in today's dollars, inflation is already handled by using a real return. A 5% real return is roughly a 7.5% to 8% nominal return with inflation near 2.5% to 3%.
The earlier you start, the more years compounding has to work, so the smaller the amount you need today. For a $1,500,000 goal at 65 and a 5% real return:
| Current age | Years to grow | Coast FIRE number today |
|---|---|---|
| 25 | 40 | $213,069 |
| 30 | 35 | $271,935 |
| 35 | 30 | $347,066 |
| 40 | 25 | $442,954 |
| 45 | 20 | $565,334 |
| 50 | 15 | $721,526 |
A 25-year-old needs less than a third of what a 50-year-old needs to reach the same retirement. This is the strongest argument for saving hard in your twenties, even if you plan to ease off later.
Small changes in the expected return move the coast number a long way, because the discounting runs over decades. For the same 30-year-old with a $1,500,000 goal:
| Real return | Coast FIRE number today |
|---|---|
| 4% | $380,123 |
| 5% | $271,935 |
| 6% | $195,158 |
| 7% | $140,494 |
The gap between 4% and 7% is almost $240,000. If your plan only works at 7%, it does not have much room for a bad decade. Many people run the numbers at 4% or 5% and treat anything better as a bonus.
Hitting your coast number does not mean you can stop working. It means your paycheck only has to cover your current life. That opens up choices that are hard to make while you are also funding retirement:
Most people who reach Coast FIRE keep contributing something anyway, if only to capture an employer 401(k) match. Every extra dollar you add pulls your retirement date earlier or gives you a cushion against weak markets.
Coast FIRE relies on decades of growth that you are no longer adding to, so a few things deserve attention. A long stretch of poor returns early on can leave you behind schedule with less time to recover. Your spending in retirement may turn out higher than you expect, especially for health care. And the plan assumes you leave the money invested; dipping into it for an emergency resets the clock. It is worth checking your progress every year or two by plugging your current balance back into the calculator.
When you are ready to plan the full number, the FIRE calculator shows how long it takes to reach it at your current savings rate. To test a plan against many possible market paths, try the Monte Carlo retirement calculator.
Coast FIRE means you have invested enough that, with no further contributions, your savings will grow to your full retirement number by your chosen retirement age. You still work to cover current expenses, but you no longer need to save for retirement.
Divide your annual retirement spending by your withdrawal rate to get your FIRE number, then divide that by (1 + real return) raised to the number of years until retirement. For $60,000 of spending at 4%, a 5% real return, and 35 years, that is $271,935.
Use a real return, which is your expected return minus inflation. That keeps the whole calculation in today's dollars, so the spending figure you enter means what it says.
In theory, yes. In practice, most people keep saving at least enough to get an employer match, because extra contributions protect against weak returns and can bring the retirement date earlier.
This calculator does not. If you expect a benefit, you can lower your retirement spending input by that amount, which lowers both your FIRE number and your coast number.
The formula and a worked example are on our methodology page. Returns are not guaranteed; this is an educational estimate, not financial advice.