Coast FIRE: The Strategy That Lets You Stop Saving for Retirement

What is Coast FIRE?

Coast FIRE is a milestone within the broader FIRE movement where your current invested assets are projected to grow to your full retirement target by your target retirement age without further contributions, based on an assumed return.

Once you reach a Coast FIRE estimate, the financial pressure may change. You still need to cover current living expenses, and the projection should be reviewed as returns, fees, inflation, spending, and your retirement date change. If the assumptions continue to hold, additional retirement contributions may no longer be required to reach the modeled target.

The term "coasting" is apt: after years of aggressive saving and investing, you shift out of high gear and let momentum carry you forward.

How to calculate your Coast FIRE number

Your Coast FIRE number is your full FIRE number mathematically discounted back to today's dollars, accounting for the compound growth that will occur between now and retirement.

The formula:

Coast FIRE Number = Full FIRE Number ÷ (1 + annual return)^years to retirement

Step-by-step example:

1. Determine annual retirement expenses: $60,000/year
2. Calculate full FIRE number: $60,000 × 25 = $1,500,000
3. Inputs: Current age 35, target retirement age 60, expected return 7%
4. Years to retirement: 60 - 35 = 25 years
5. Coast FIRE calculation: $1,500,000 ÷ (1.07)²⁵ = $1,500,000 ÷ 5.427 = $276,500

At age 35, $276,500 left invested for 25 years would grow to approximately $1,500,000 at a steady 7% annual return. This is an illustrative projection, not a guaranteed outcome.

Why age matters

Because Coast FIRE discounts a future target back to today, the number rises the closer you are to your target retirement age — there's simply less time left for compounding to do the work. Using the same $60,000/$1,500,000/7% example, an illustrative Coast FIRE number is roughly $81,800 at age 22 versus about $543,600 at age 50, targeting retirement at 65. Every year you delay starting is another year of compounding you lose, and the required amount rises accordingly.

Whether either figure is practical depends on income, expenses, existing savings, taxes, and actual returns. For the complete set of tables across ages, retirement ages, and spending levels, see the Coast FIRE Number by Age guide. For your own numbers, use the Coast FIRE calculator.

Why Coast FIRE is achievable much earlier than full FIRE

Full FIRE typically requires 15-25 years of aggressive saving to accumulate $1M-2M+. Coast FIRE often requires only 5-10 years to reach a much smaller number.

Example: Jennifer, age 28, earns $75,000/year and saves aggressively: - Saves $2,500/month - Current savings: $15,000 - Expected return: 7%

At this pace, Jennifer reaches a $112,500 interim target in approximately 35 months under monthly compounding with end-of-month contributions.

Her full FIRE number of $1,500,000 would take approximately 21 years in total at the same modeled rate and contribution amount.

The comparison illustrates how an interim Coast FIRE milestone can arrive much earlier than the full target. Neither timeline secures a retirement outcome because returns and future spending are uncertain.

What changes at Coast FIRE

Reaching Coast FIRE is a fundamental shift in your relationship with money and work.

Before Coast FIRE: You need to save aggressively. Your income must cover both current expenses AND retirement contributions. High-income jobs become necessary. Career decisions are constrained by salary requirements.

After Coast FIRE: Under the modeled assumptions, you no longer need retirement contributions to cover current expenses. A lower-paying job you love may become viable. Part-time work may become sufficient. Career sabbaticals or a move to a lower cost-of-living area become options to weigh.

Reaching Coast FIRE changes what your income needs to cover — it does not by itself mean you are ready to retire, and it does not remove the need for an emergency fund, insurance, or ongoing income while you're coasting. If markets underperform your assumptions, the portfolio may not reach the full target on schedule; see "What if markets don't cooperate?" below.

Coast FIRE vs other FIRE variants

The FIRE movement has spawned several sub-strategies, each with different targets and timelines:

Coast FIRE is unique in that it doesn't require you to actually retire — just to eliminate the retirement saving obligation from your income requirements.

The Flamingo FIRE strategy: Coast FIRE's practical cousin

Flamingo FIRE combines Coast FIRE with Barista FIRE: save aggressively to reach Coast FIRE, then shift to part-time or flexible work that covers current expenses.

The result: no retirement savings pressure, lower work requirements, and a full retirement portfolio waiting at the end without ever contributing again.

Example: Marcus reaches Coast FIRE at 33 with $165,000 invested (targeting retirement at 65 on $55,000/year). He leaves his stressful $120,000/year corporate job and takes a $45,000/year remote consulting role that covers his living expenses. His $165,000 grows untouched to $1,375,000 by age 65.

He "worked" for 32 more years but with dramatically lower stress and more flexibility, while staying on track toward a full retirement number under these modeled assumptions.

How to accelerate reaching Coast FIRE

Increase your savings rate in the early years

The Coast FIRE number is smallest when you're young. If you can save aggressively for 3-7 years in your 20s, you can potentially reach Coast FIRE before 30, opening up decades of potential compounding ahead — provided the return and spending assumptions used continue to hold.

Even $500-1,000/month invested consistently in your early 20s can reach a Coast FIRE estimate by age 28-32 under these assumptions, depending on spending level; use the calculator to check your own numbers.

Minimize fees and maximize returns

At the Coast FIRE stage, fees matter because they reduce the return available for compounding. On a $200,000 starting balance over 35 years, the modeled difference between a 7% annual return and a 6.5% net return is approximately $323,000.

Use total market index funds with expense ratios under 0.10%.

Use tax-advantaged accounts first

U.S. Roth IRAs can provide tax-free qualified distributions, while traditional 401(k) accounts generally defer tax until withdrawal. Eligibility, plan terms, fees, and future tax treatment all affect the comparison with a taxable account.

For 2026, the U.S. IRA contribution limit is $7,500 and the employee 401(k) deferral limit is $24,500, subject to eligibility and catch-up rules. See the IRS 2026 retirement-plan limits. Account order should reflect your plan match, fees, taxes, liquidity needs, and jurisdiction.

Don't touch it after you reach Coast FIRE

The entire Coast FIRE strategy depends on leaving the invested amount untouched. Any withdrawals restart the compounding clock and may push you below your Coast FIRE number.

Build a separate emergency fund (6-12 months of expenses in cash) before reaching Coast FIRE so you never need to touch your investment portfolio.

The return assumption matters as much as age

The expected-return input drives the result at least as much as your age does: for a 35-year-old targeting retirement at 65 on a $1,500,000 FIRE number, a conservative 5% return assumption requires a Coast FIRE number roughly $150,000 larger than a 7% assumption. See the Coast FIRE Number by Age guide for the full return-rate sensitivity table, or test your own rate directly on the Coast FIRE calculator — the calculator does not assume any single rate is correct for your situation.

What if markets don't cooperate?

Coast FIRE depends on future returns meeting your assumptions. This is the primary risk: if markets return 4% instead of 7% over your coasting period, your portfolio won't reach the full FIRE number.

Mitigation strategies:

1. Use a conservative return assumption. Plan on 6% rather than 8% to build in a margin of safety.

2. Continue small contributions if your income allows. Coast FIRE means you don't have to contribute — not that you shouldn't if you can.

3. Remain willing to work slightly longer if needed. If at age 60 your portfolio is at 85% of your FIRE number due to poor returns, a few extra years of work or part-time income bridges the gap.

4. Keep your Coast FIRE number updated. Recalculate annually as your spending expectations, return assumptions, and timeline evolve.

Frequently asked questions

Is Coast FIRE the same as "set it and forget it" retirement? Not exactly. You still need to monitor your investments, rebalance periodically, and ensure you're on track. But you no longer need to actively contribute, which removes one specific source of financial pressure: the need to fund retirement contributions out of current income.

What happens to Coast FIRE if I change my retirement spending target? It scales directly. If you decide you want to spend $80,000/year instead of $60,000/year in retirement, your full FIRE number rises from $1.5M to $2M, and your Coast FIRE number rises proportionally. Recalculate any time your target changes.

Can I use Coast FIRE if I have a pension or Social Security? Potentially. Model pension or U.S. Social Security income only from the age when it is expected to begin, and fund the years before that date separately. Benefit amounts, eligibility, taxes, and claiming ages vary, so use a personal estimate rather than subtracting delayed income from every retirement year.

What if I reach Coast FIRE but then have a major life expense? If you need to withdraw from your Coast FIRE portfolio for a major expense, you may fall below your Coast FIRE number and need to resume saving until you rebuild it. This is why maintaining a separate emergency fund and not conflating Coast FIRE savings with accessible savings is critical.

At what age is Coast FIRE most impactful? The younger you reach Coast FIRE, the more compounding time remains: reaching it at 25 leaves roughly 40 years of growth without further contributions, versus about 15 years if reached at 50, requiring a much larger initial amount. Whether prioritizing an earlier Coast FIRE date is worth trading off against other goals — a higher spending target, career flexibility now, or simply personal circumstances — depends on individual priorities, not just the math.

Does Coast FIRE work outside the US? The compound-growth formula is not country-specific, but taxes, account rules, inflation, investment access, fees, pensions, healthcare, and retirement systems vary by jurisdiction. Adapt the assumptions to the country where you save and expect to retire.