Coast FIRE is the moment you can stop saving for retirement and still retire on time. Not stop working. Just stop adding money to your retirement accounts.

It is the point where the money you have already invested, left completely untouched, will grow into a big enough nest egg to cover your retirement by the time you reach your target retirement age. Once you hit it, your existing savings do the heavy lifting on their own. You still need income to cover today’s bills, so most people keep working. You are coasting to the finish line.

The idea rests on one of the most reliable forces in personal finance: compound growth over a long stretch of time. A sum left alone for 25 or 30 years can more than quadruple, and Coast FIRE is really just a way of asking whether the sum you already have is big enough to do that.

There are three moving parts.

Step 1. Figure out the nest egg you will need. Decide how much you want to spend per year in retirement, then divide that by your safe withdrawal rate, which is the percentage of your savings you plan to pull out each year without running dry.

nest egg needed = annual retirement spending / safe withdrawal rate

A 4% safe withdrawal rate is the common starting point, which is the same as saying you need 25 times your annual spending. If you want to spend $40,000 a year, you need $40,000 / 0.04 = $1,000,000.

Step 2. Grow your current savings untouched. Take what you have invested today and project it forward to your retirement age, adding no new contributions.

future value = current savings × (1 + real return) ^ years until retirement

The word real matters here. A real return is your return after subtracting inflation. Using a real return keeps everything in today’s dollars, which is what makes the final comparison honest.

Step 3. Compare the two numbers. If the future value from Step 2 is equal to or greater than the nest egg from Step 1, you have hit Coast FIRE. If it falls short, you have not reached it yet, and the gap tells you how much more your starting balance needs to grow or how much more you need to add.

Meet Maya. She is 35, she wants to retire at 65, and she wants to spend about $40,000 a year in retirement (in today’s dollars). She has $250,000 invested. We will assume a 5% real return and a 4% safe withdrawal rate. These are illustrative figures, not a recommendation.

Step 1: the nest egg Maya needs. $40,000 / 0.04 = $1,000,000. That is her target, expressed in today’s dollars.

Step 2: grow her savings for 30 years, untouched. She has 65 minus 35 = 30 years. At a 5% real return:

$250,000 × (1.05) ^ 30 = $250,000 × 4.3219 = about $1,080,000

Because we used a real (after-inflation) return, that $1,080,000 is already in today’s dollars. No extra inflation adjustment needed.

Step 3: compare. $1,080,000 is greater than $1,000,000. Maya has already passed Coast FIRE. She could stop contributing to retirement accounts right now and, if her investments earn about 5% above inflation on average, she is on track to retire at 65 with slightly more than she needs. She still has to earn enough to pay her bills for the next 30 years. But the retirement-saving job is, in a sense, done.

If Maya had only $200,000 instead, the math would read $200,000 × 4.3219 = about $864,000, short of the $1,000,000 target. She would not be at Coast FIRE yet, and the gap would tell her she needs to keep contributing, retire a little later, or spend a little less.

If you project growth using a nominal return (say 8%) but forget that inflation is quietly shrinking the value of a dollar, you end up with a future number that looks huge and buys much less than you think. By using a real return, both sides of the comparison sit in today’s money, so a $1,000,000 target and a $1,080,000 projection mean what they appear to mean.

Exityear Lite keeps everything on one consistent basis. Your investments grow at the nominal return you enter, and your future expenses and withdrawals rise with inflation. Checking whether your balance out-grows that inflating target is mathematically the same as the real-return test above, so the Coast FIRE age it reports matches this today’s-dollar reasoning. Per-account growth overrides use the same nominal basis.

This is the part people mix up most, so here it is plainly.

• Regular FIRE means you have already saved the full nest egg. The whole $1,000,000 exists today, and you could retire now and live off it.
• Coast FIRE means you have saved enough that it will become the full nest egg on its own by your retirement age, without another dollar of contributions. You are not financially independent yet. You are on an automatic path to it.

Coast FIRE almost always arrives years, sometimes decades, before full FIRE. Maya is at Coast FIRE at 35 but will not reach full FIRE until her balance actually crosses $1,000,000 in today’s dollars, somewhere in her late 50s or early 60s.

For the fuller comparison across every variant, see FIRE, Coast FIRE, Lean FIRE, and Barista FIRE. And to see how taxes and debt shift these numbers in real life, see a FIRE calculator that includes taxes and debt.

The hand calculation above assumes a single steady return and no taxes, no debt, and no changes along the way. Real life is messier. Exityear Lite runs this projection month by month all the way to your life expectancy, tracks your accounts separately, and marks the exact age it detects Coast FIRE (or tells you if it is not reached). It runs entirely in your browser. No account, no sign-up, and none of your numbers ever leave your device.

One honest caveat: any projection like this is an estimate built on assumptions about returns you cannot control. It is a planning tool, not financial advice, and it is only as good as the inputs behind it.

Open the calculator and try your own figures.

Does hitting Coast FIRE mean I can stop working?
No. It means you can stop saving for retirement. You still need income to cover your day-to-day expenses until you actually retire. What changes is that money you used to set aside for retirement is now free for other things.

What safe withdrawal rate should I use?
Many people start with 4%, which implies a nest egg of 25 times your annual spending. A lower rate is more cautious and needs a larger nest egg. Exityear Lite defaults to 4% and lets you set your own.

Why does the worked example use a real return?
Because the hand calculation compares a future value to a spending target, and mixing today’s dollars with future inflated dollars is misleading. Using a real return keeps both sides in today’s money. The tool itself grows your investments at the full nominal return and inflates your future expenses instead, which reaches the same Coast FIRE point.

Can I lose Coast FIRE after reaching it?
Yes. A long stretch of poor returns, higher planned spending, or an earlier retirement age can push the target back out of reach. Re-check your projection periodically rather than treating it as permanent.

Is Coast FIRE the same as being financially independent?
No. Full FIRE means you already have the entire nest egg today. Coast FIRE means you are on track to have it by your retirement age without further saving. Coast FIRE usually comes first, often much earlier.