Last verified: September 23, 2026.
Your coast FIRE number is the amount you need invested right now so that, without adding another dollar, it grows into your full retirement target by the time you stop working. A 35-year-old who wants $40,000 a year in retirement at 65 needs about $1,000,000 at a 4% withdrawal rate, and roughly $139,103 invested today to coast there on a 6.8% real return.
Hit that figure and you can stop saving for retirement. You still work to pay today's bills, but the retirement part is handled. This guide shows the formula, the numbers by age, what happens when returns disappoint, and how coasting differs from barista FIRE. Run your own figures in our Coast FIRE calculator. It's researched from published studies and government sources, and it isn't financial advice.
The formula
Two steps. First your FIRE number, then discount it back to today.
FIRE number = yearly spending ÷ withdrawal rate
Coast FIRE number = FIRE number ÷ (1 + real return)years until retirement
The 4% withdrawal rate comes from William Bengen's 1994 study of historical portfolios, which found that a first-year withdrawal of 4%, then raised with inflation, should be safe for at least 30 years. The Trinity study reached a similar conclusion four years later, reporting that 3% and 4% withdrawal rates are "extremely unlikely to exhaust any portfolio" over the periods it tested. Both were built around a 30-year retirement, which matters if you plan to retire at 45.
Use a real return, not the headline 10%
This is where most coast FIRE math goes wrong. If your spending target is in today's money, the growth rate has to be a real return, meaning after inflation. US stocks have compounded at roughly 9.8% a year including dividends since 1928, calculated from Damodaran's annual returns dataset at NYU Stern. Take 3% inflation off that and you're at about 6.8% real, which is the figure to use.
Plug 10% into a target expressed in today's dollars and you'll flatter your coast FIRE number by a wide margin.
Coast FIRE numbers by age
All of these assume a $1,000,000 target, retirement at 65 and a 6.8% real return.
| Your age | Years of compounding left | Coast number |
|---|---|---|
| 25 | 40 | $72,074 |
| 30 | 35 | $100,129 |
| 35 | 30 | $139,103 |
| 40 | 25 | $193,247 |
| 45 | 20 | $268,467 |
| 50 | 15 | $372,965 |
| 55 | 10 | $518,138 |
Every five years you wait, the bar rises by roughly 40%. That's the cost of lost compounding, and it's the strongest argument for front-loading savings in your twenties.
What happens if returns disappoint
Most coast FIRE articles pick one return and stop. The assumption does more work than any other input, so here's the same 35-year-old under three of them.
| Nominal return | Real return after 3% inflation | Coast number at 35 |
|---|---|---|
| 10% | 6.8% | $139,103 |
| 8% | 4.9% | $241,215 |
| 7% | 3.9% | $318,862 |
Two percentage points of return more than doubles what you need. Your withdrawal rate moves the target too, though less violently: at 3.5% the coast number rises to $158,975, and at 3% it's $185,471.
The safer way to use this is to coast on the conservative figure and treat the optimistic one as upside. FINRA's own guidance on retirement withdrawals notes that expert opinion clusters in the 3% to 5% range and that you want to give a portfolio room to recover after a bad market.
Coasting isn't permanent, so recheck it
Nobody says this part out loud. Once you stop contributing, you lose your shock absorber. A 30% drawdown in the year after you quit saving doesn't just dent the balance, it resets the compounding your whole plan rests on, and you have no new money going in to buy the recovery.
Check your coast FIRE number every year, at the same time you rebalance. If the market has fallen or your spending target has risen, the fix is small if you catch it early: a few hundred a month for a couple of years, rather than a panic at 55.
Coast FIRE vs barista FIRE
These get mixed up constantly, including by big finance sites. The difference is whether you're touching the portfolio.
| Coast FIRE | Barista FIRE | |
|---|---|---|
| Portfolio | Untouched, left to compound | Partly drawn down already |
| Work | Covers all your current costs | Covers part of your costs |
| Typical stage | Mid-career | Closer to full retirement |
| Main appeal | Stop saving, take the job you want | Cut hours, often for health cover |
Both need earned income. Coasting just needs enough to pay the bills, which is why people at this stage switch to lower-paid work they actually enjoy.
Where the money sits matters
A coast FIRE number is a pre-tax figure unless all of it is in a Roth. $500,000 in a traditional 401(k) is not $500,000 of spending, because withdrawals are taxed as income. Roth money is already taxed. A taxable brokerage account sits in between, with dividends and gains taxed along the way.
Access matters too. Most retirement accounts are locked until 59½, with exceptions, so anyone coasting to a finish line in their forties or early fifties needs a taxable account or a Roth ladder to bridge the gap. Getting there still means filling the tax-advantaged space first: the 2026 limits are $24,500 for a 401(k) and $7,500 for an IRA. Our comparison of 403(b) and 401(k) plans covers which account suits which job.
Health insurance is the real reason people keep working
Ask anyone coasting why they haven't gone further and the answer is usually health cover, not the portfolio. If you leave employer insurance, Marketplace subsidies are based on your income for the year you want coverage, not last year's salary, which works in favor of someone whose earnings have just dropped. Price a plan before you hand in your notice, because this line item decides more early retirements than the coast number does.
How to work out your own coast FIRE number
- Add up the yearly spending you want in retirement, in today's money.
- Divide by your withdrawal rate. 4% is the standard; 3.5% if you plan a long retirement.
- Count the years until you want to retire.
- Discount the target back at a real return, around 5% to 7%.
- Compare it with what you have invested today, and recheck every year.
The calculator does all five steps and adds the age you reach the target at your current savings rate. For the other end of the journey, see how long your money will last in retirement.
Frequently asked questions
What is coast FIRE?
Coast FIRE is the point where your invested savings will grow into your retirement target on their own, so you can stop contributing. You keep working to cover current expenses, but you no longer save for retirement.
How do I calculate my coast FIRE number?
Divide your yearly 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. Use a return after inflation, not the headline market average.
What is a good coast FIRE number at 30?
For a $1,000,000 target at 65 with a 6.8% real return, about $100,129. Change any of the three assumptions and the figure moves, which is why it's worth running your own numbers rather than copying someone else's.
What's the difference between coast FIRE and barista FIRE?
Coast FIRE leaves the portfolio untouched while your job covers all your costs. Barista FIRE means you're already drawing on savings and part-time work fills the gap, often chosen for the health insurance.
Can you lose coast FIRE status?
Yes. A bad market or higher spending plans can push the target above your balance, and with no contributions going in there's nothing buying the recovery. Recheck the number once a year and resume saving for a while if you've fallen behind.
