Coast FIRE Calculator
The amount you need today so compound interest finishes the job — no more saving required.
How much you'd spend per month in retirement, in today's money.
Total in your retirement / brokerage accounts today.
How much you invest each month right now.
Advanced assumptions
Defaults match our FIRE Calculator: 11% nominal return, 2.5% inflation, 4% withdrawal rate (8.5% real return based on long-run S&P 500 averages). Adjust if you want a more conservative view.
Projection assumptions
Stock market avg. ~11%
Historical avg. ~2-3%
The 4% rule is FIRE standard
Your Coast FIRE Number
$51,785
Coast at age 34 (around —)
After that, you never need to invest another dollar toward retirement.
Your full FIRE target is $900,000
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Want to track this for real? See your actual progress against this milestone month-over-month.
Create my account| FIRE flavor | Annual spend | FIRE target | Coast today |
|---|---|---|---|
Lean FIRE 0.7× your monthly expenses | $25,200 | $630,000 | $36,249 |
Coast FIRE Your monthly expenses (this calculator) | $36,000 | $900,000 | $51,785 |
Barista FIRE Half from portfolio, half from part-time work | $36,000 | $450,000 | $25,892 |
Regular FIRE Your monthly expenses, full coverage | $36,000 | $900,000 | $51,785 |
Fat FIRE 1.5× your monthly expenses | $54,000 | $1,350,000 | $77,677 |
Updated June 2026
What is Coast FIRE?
Coast FIRE is the moment you can stop investing for retirement and still retire on time. You've invested enough early in life that compound interest alone carries the portfolio to your full FIRE number — usually by age 65.
The trick is doing the math backwards. Pick your full FIRE number (annual expenses × 25). Then ask: how much would I need invested today so that, growing at the historical real return, it reaches that number by retirement age? That's your Coast FIRE number. Once you hit it, you can switch jobs, go part-time, take a sabbatical, or just stop contributing — your retirement is on autopilot. Read the full Coast FIRE explainer →
The Coast FIRE Formula
Coast FIRE math is four equations stacked together. Every Coast FIRE calculator on the internet uses these — we just put yours in front:
1. Your full FIRE target
FIRE Target = Annual Expenses ÷ Withdrawal Rate
Example: $3,500/month → $42,000/year ÷ 4% = $1,050,000
2. Your Coast FIRE number
Coast FIRE = FIRE Target ÷ (1 + Real Return)^Years to Retirement
Example: $1,050,000 ÷ (1.085)^35 = ~$60,000 needed today at age 30
3. Your retirement income
Annual Withdrawal = Total Savings × Withdrawal Rate
Example: $1,050,000 × 4% = $42,000/year
4. Monthly income at retirement
Monthly Income = (Total Savings × Withdrawal Rate) ÷ 12
Example: ($1,050,000 × 4%) ÷ 12 = $3,500/month
Coast FIRE With a Pension or Social Security
A pension or Social Security lowers your Coast FIRE number, because guaranteed income covers part of your retirement spending — your portfolio only has to fund the gap. This calculator subtracts your expected benefit from your monthly expenses, recalculates the FIRE target at the same withdrawal rate, and adds back any 'bridge' years between retiring and your first benefit check.
Adjusted FIRE target = (Monthly expenses − Monthly benefit) × 12 ÷ Withdrawal rate + Bridge years × Annual benefit
Worked example
Spending $3,500/month with a $2,000/month benefit starting at 67 and retiring at 65: the gap is $1,500/month → $450,000 at a 4% withdrawal rate, plus 2 bridge years × $24,000 = $498,000 — instead of $1,050,000 with no benefit. Your Coast FIRE number scales down with it: at age 30 (8.5% real return), that's roughly $29,000 needed today instead of $60,000.
Why this matters
The average U.S. Social Security retirement benefit is $2,071 per month as of January 2026, after the 2.8% cost-of-living adjustment. At a 4% withdrawal rate, that income stream does the job of a ~$621,000 portfolio — money many Coast FIRE plans pretend doesn't exist. Counting it can move your coast date forward by years. Source: Social Security Administration, 2026 COLA Fact Sheet →
State pensions in Europe
The same math applies to European state pensions — enter your projected Czech state pension, German Rente, or UK State Pension as the monthly benefit and set the start age to your country's pension age. Combined with the currency selector above, this makes the calculator work for EU FIRE plans, not just US ones.
Coast FIRE for Couples
Couples reach Coast FIRE with one combined number, not two separate ones. Toggle couple mode above and the calculator adds both partners' portfolios and monthly contributions together, keeps household expenses as one figure, and compounds the combined pot until the earlier of your two retirement dates. One pot, one household plan — usually a noticeably earlier coast date than either partner alone.
The model: combined invested assets and combined contributions grow at the same real return, and the compounding horizon ends when the FIRST partner retires. That is deliberately conservative — money is fungible across accounts, but the portfolio must be ready the day the first paycheck stops. If one of you plans to keep working past that date, your real coast date is earlier than what we show, never later.
Two practical effects show up in couple mode: a second contributor usually pulls the coast date years closer, and an age gap means the younger partner's longer compounding runway can't be used past the older partner's retirement — the calculator tells you which partner's date is binding.
Coast FIRE Number by Age
| Your age | Years to 65 | At your expenses | At 1.5× your expenses |
|---|---|---|---|
| 20 | 45 | $22,904 | $34,355 |
| 25 | 40 | $34,439 | $51,659 |
| 30 | 35 | $51,785 | $77,677 |
| 35 | 30 | $77,866 | $116,800 |
| 40 | 25 | $117,084 | $175,627 |
| 45 | 20 | $176,055 | $264,082 |
| 50 | 15 | $264,726 | $397,089 |
Assumes 8.5% real return (11% nominal − 2.5% inflation), 4% safe withdrawal rate. Today's purchasing power.
Coast vs Barista vs Lean vs Fat FIRE
Coast FIRE isn't a finish line — it's a release valve. Here's how it compares to the other flavors:
- Coast vs Barista: Barista FIRE means you've saved enough that part-time income can cover the gap to retirement. Coast FIRE means you've saved enough that any income covers the gap — you don't need the portfolio to pay anything yet.
- Coast vs Lean: Lean FIRE is a finish line at a low spend. Coast FIRE is a halfway marker — you can keep working at any income level, just without the pressure to keep saving.
- Coast vs Fat: Fat FIRE asks for a much bigger portfolio (1.5–2× a regular FIRE number). The Coast FIRE math still works — you just need a bigger Coast number today.
The next level: plan the whole life, not just the number
You now know the amount to reach before you can stop contributing. Add the car, the child and the year off, and see your net worth and monthly income run to age 90 across 400 simulated futures — no account.
How to Use This Calculator
Three steps, plus optional couple and pension settings:
- 1
Enter your age and the age you want to retire. Default 65.
- 2
Enter how much you'd spend per month in retirement — in today's money.
- 3
Enter what you've already invested. The calculator shows your Coast FIRE number and the age you can stop contributing.
- 4
Optional: switch on couple mode or add a pension / Social Security benefit, and override the 11% return / 2.5% inflation / 4% withdrawal defaults under Advanced assumptions. Use 'Copy link' to save or share the result.
Tips for Hitting Coast FIRE Early
The earlier you reach Coast FIRE, the more options you buy. Seven things that move the needle:
Front-load contributions in your 20s and early 30s — every $1,000 invested at 25 is worth ~$15,000 at 65 (8.5% real).
Use tax-advantaged accounts first (401(k) match, Roth IRA, HSA) — compounding tax-free supercharges the Coast date.
Index funds, not stock picks — Coast FIRE math assumes broad-market returns. Concentrated bets distort the numbers in both directions.
Recalculate yearly — lifestyle creep raises your FIRE target, which raises your Coast number.
Keep an emergency fund — Coast FIRE doesn't mean stop earning. You still need 3-6 months of expenses outside the portfolio.
After Coast FIRE, keep contributing if you can — the floor becomes a buffer against down markets.
Don't quit the day after you hit Coast — give the portfolio at least a year above the line to confirm you weren't surfing a bull market.
Assumptions & Methodology
Every number on this page follows the same conventions as our FIRE Calculator. The defaults are deliberately visible — and everything below can be overridden in Advanced assumptions:
- Returns: 11% nominal annual return by default (long-run S&P 500 average, dividends reinvested) minus 2.5% inflation = 8.5% real return.
- Today's money everywhere: all inputs and outputs are in today's purchasing power. Compounding uses the real return, so no number needs a separate inflation adjustment.
- Withdrawal rate: 4% by default (Trinity Study). Your FIRE target = annual expenses ÷ withdrawal rate.
- Pension / Social Security: adjusted target = (expenses − benefit) × 12 ÷ withdrawal rate + bridge years × annual benefit, capped at the no-benefit target. No growth is credited inside the bridge bucket (slightly conservative).
- Couple mode: combined portfolio and contributions, compounded to the earlier of the two retirement dates (conservative — the money must be ready when the first paycheck stops).
- Not modeled: taxes, investment fees, and sequence-of-returns risk. Treat results as a planning guideline, not a guarantee.
Frequently Asked Questions
What is Coast FIRE?
Coast FIRE is the moment you have enough invested that compound interest alone — with no more contributions — will grow to your full FIRE number by retirement age. You can still work to cover monthly expenses, but you no longer need to save for retirement. It's the floor, not the ceiling.
How do I calculate my Coast FIRE number?
Two steps. First, find your full FIRE number: annual expenses ÷ withdrawal rate (usually 4%). Then divide by (1 + real return)^(years until retirement). At our default 8.5% real return and 35 years to 65, a $1.05M FIRE number means you need about $60,000 invested today.
What's the Coast FIRE formula?
Coast FIRE = FIRE Target ÷ (1 + Real Return)^Years to Retirement. Where FIRE Target = Annual Expenses ÷ Withdrawal Rate, and Real Return = Nominal Return − Inflation. This calculator runs all of that for you.
How much do I need for Coast FIRE at age 30?
Roughly 6% of your full FIRE number, if you're retiring at 65 and using our default 8.5% real return. For $1.05M FIRE (covers $3,500/month in expenses), that's about $60,000 invested today. Use the calculator above for your exact numbers.
Coast FIRE vs Barista FIRE — what's the difference?
Coast FIRE means your portfolio will reach FIRE on its own — you still earn enough to cover today's bills but can stop contributing. Barista FIRE means your portfolio doesn't quite cover full retirement yet, so you keep a part-time job indefinitely whose income closes the gap. Coast is upstream of Barista.
Coast FIRE vs Lean FIRE vs Fat FIRE — which is right for me?
Lean / Regular / Fat FIRE describe the size of the finish line (low spend, mid spend, luxury spend). Coast FIRE describes a milestone on the way — you can have Lean Coast FIRE, Regular Coast FIRE, or Fat Coast FIRE depending on your monthly expenses. Coast and the others aren't competing — they answer different questions.
Can I still contribute after I reach Coast FIRE?
Absolutely — many people do. Coast FIRE is permission to stop, not a mandate. Common patterns: keep the 401(k) match (it's free money), drop discretionary contributions and redirect them to lifestyle/sabbaticals/business, or keep contributing at full pace and reach full FIRE 5-10 years sooner.
What return rate should I assume — 7% or 10%?
We default to 11% nominal − 2.5% inflation = 8.5% real return, based on long-run S&P 500 averages. Many calculators use 7% real (more conservative). Both are defensible. Open Advanced assumptions and try both — if your Coast date doesn't change by more than 2-3 years, the assumption isn't the limiting factor; your contribution rate is.
Does Coast FIRE account for inflation?
Yes. Every number you enter and every number we show is in today's purchasing power. We compute compound growth at the real (inflation-adjusted) rate, so the FIRE target you see is the spending power you'll actually have — not a nominal number 35 years from now that buys half as much.
Is Coast FIRE realistic for the average earner?
Yes, if you start early. A 25-year-old who saves $850/month for ~6 years reaches Coast FIRE for a $1M target. The math gets harder the later you start — every 5 years of delay roughly doubles the required Coast number. But late is still better than never.
What happens to my Coast FIRE number if the market crashes?
Your portfolio drops, so the formula now says you owe more contributions to get back to the Coast line. The good news: Coast FIRE assumes 30-40 year horizons, and the U.S. stock market has never had a 20-year period with negative real returns. Most people who hit Coast FIRE and then see a 30% drawdown resume contributions for a year or two and get back on track.
Should I use 4% or 3.5% as my withdrawal rate?
4% is the original Trinity Study guideline and still the most common default — gives a 95% historical success rate over 30 years. 3.5% is the more conservative modern guideline (Bengen and others, for early retirees with 40-50 year horizons). Lower withdrawal rate = larger FIRE target = larger Coast FIRE number. Open Advanced assumptions and try 3.5% to see the impact.
Does a pension or Social Security lower my Coast FIRE number?
Yes — substantially. Guaranteed income covers part of your retirement spending, so the portfolio only has to fund the gap: (expenses − benefit) × 12 ÷ withdrawal rate, plus any bridge years before benefits start. A $2,000/month benefit at a 4% withdrawal rate replaces roughly $600,000 of portfolio. Toggle the pension section above to see your own adjusted number.
How does Coast FIRE work for couples?
As one household: combine both portfolios and both monthly contributions, keep expenses at the household level, and compound to the earlier of the two retirement dates. Couple mode above does this automatically and shows which partner's retirement date binds the timeline. A second contributor usually moves the coast date years closer.
Can I save or share my result?
Yes — click 'Copy link to this result' under the result card. All your inputs are encoded in the URL itself, so anyone opening the link sees exactly your scenario. Nothing is stored on our servers, and no signup is needed.
Want to actually hit this date?
This number assumes perfectly steady contributions. Reality isn't. Track whether you're ahead of plan — with your real accounts.
Create my accountNot financial advice
This calculator is for educational use. Past returns don't predict future returns. Talk to a licensed financial advisor before making investment decisions, and treat any single 'number' (FIRE, Coast FIRE, Barista FIRE) as a guideline, not a guarantee.
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