Coast FIRE Calculator
Find the exact amount you need invested today so you can stop saving for retirement and let compound growth do the rest. Uses the 4% safe withdrawal rule and historical 7% real return assumption from long-term S&P 500 data.
Last updated: April 2026 · Based on Trinity Study (1998) and historical S&P 500 returns
In today's dollars — real return handles inflation
Coast FIRE variations at your age
| Variant | Annual spending | Full FIRE # | Coast # (age 32) |
|---|---|---|---|
| Lean FIRE | $42,000 | $1,050,000 | $112,596 |
| Regular FIRE | $60,000 | $1,500,000 | $160,852 |
| Fat FIRE | $120,000 | $3,000,000 | $321,704 |
Coast number = FIRE number / (1 + 7%)^33 years to retirement at 65
Frequently asked questions
What is Coast FIRE?
Coast FIRE is a flavor of the Financial Independence Retire Early (FIRE) movement. It is the point at which you have saved enough money that, if you stop contributing entirely and just let it grow, it will reach your full FIRE number by your target retirement age. You still need to earn enough to cover your current expenses, but you no longer need to save a penny for retirement. This is often the most practical FIRE milestone because it unlocks career flexibility decades before full financial independence.
How is Coast FIRE calculated?
Coast FIRE uses the compound growth formula in reverse. First calculate your FIRE number (annual expenses divided by your safe withdrawal rate, typically 4%). Then discount that number backward by the expected real return over the years until retirement. Formula: Coast FIRE Number = FIRE Number / (1 + r)^years. Example: $60,000 annual expenses ÷ 4% = $1,500,000 FIRE number. If you are 32 and want to retire at 65, that is 33 years of growth. At 7% real return: $1,500,000 / (1.07)^33 = $156,000. That is your Coast FIRE number at age 32.
What is the 4% safe withdrawal rate?
The 4% rule comes from the Trinity Study (1998) and updated research by William Bengen. It says you can withdraw 4% of your initial portfolio value annually (adjusted for inflation) with a very high probability of not running out of money over a 30-year retirement. The rule assumes a diversified stock/bond portfolio. More conservative retirees use 3-3.5% for longer retirements (40+ years), and more aggressive retirees use 4.5-5% for shorter time horizons. Coast FIRE typically uses 4% as the default.
What real return should I assume?
Most FIRE calculators use 7% real return (return minus inflation). This comes from long-term historical data on the S&P 500: roughly 10% nominal return minus 3% inflation. Conservative planners use 5-6% to account for potentially lower future returns. Aggressive planners use 8-9% if they have a 100% stock portfolio for the long term. Note that "real return" already accounts for inflation, so your FIRE number calculation should also be in today's dollars — no need to inflate expenses separately.
What is the difference between Coast FIRE, Barista FIRE, and Lean FIRE?
Coast FIRE: you have saved enough that compound growth alone will get you to full FIRE by retirement age — you just need to cover current expenses with any job. Barista FIRE: similar to Coast FIRE but specifically refers to taking a low-stress part-time job that provides health insurance (like Starbucks, which offers benefits to part-timers). Lean FIRE: full financial independence at a very low expense level, typically $30K-$40K per year. Fat FIRE: full FI at a comfortable or luxurious level, typically $100K+ per year. Regular FIRE: somewhere in the middle, often $60K-$80K per year.
Should I stop saving once I hit Coast FIRE?
Not necessarily. Hitting Coast FIRE gives you the OPTION to stop saving, not the obligation. Many people continue saving because: (1) they want to retire earlier than planned, (2) they want to increase their retirement spending level, (3) they enjoy their work and the compounding, (4) they want a buffer against sequence-of-returns risk, or (5) they are saving for non-retirement goals (house, kids, travel). Coast FIRE is best thought of as a milestone that unlocks flexibility — you can switch to a lower-paying job you love without derailing retirement.
How does Coast FIRE handle sequence of returns risk?
Imperfectly. Coast FIRE assumes you will get roughly the historical average return between now and retirement. In practice, returns are volatile — you might get 10% for 5 years and then -20% in one year. A prolonged bear market in the last 5-10 years before retirement can wreck a Coast FIRE plan. This is called "sequence of returns risk." To mitigate: (1) keep saving even after hitting Coast FIRE, (2) plan for 5-7% real returns instead of 7%, (3) build a larger safety margin (Coast to 115% of your number), or (4) plan to work a few extra years if markets underperform.
Does Coast FIRE include Social Security?
It depends on how you calculate it. The strict Coast FIRE formula ignores Social Security — it assumes your entire retirement income comes from your investment portfolio. This is the safest approach because Social Security benefits could be reduced in the future (the trust fund is projected to pay 80% of scheduled benefits after 2033 without congressional action). If you include Social Security, your Coast FIRE number drops significantly. Example: $60K expenses, $25K Social Security, 4% SWR = only $875K needed instead of $1.5M. But betting on future Social Security benefits is riskier.
What investments should I use for Coast FIRE?
Most Coast FIRE practitioners use low-cost broad-market index funds — VTSAX, VTI, or equivalents. A common portfolio is 80-100% stocks while accumulating (because time smooths out volatility) and shifting toward 60/40 or 70/30 as retirement approaches. Tax-advantaged accounts get filled first (401k match, Roth IRA, HSA, then traditional 401k up to limit), with taxable brokerage for anything beyond. Bogleheads-style three-fund portfolios (US total market + international + bond index) are the most popular Coast FIRE implementation.
Is Coast FIRE realistic for average earners?
Yes, especially for people who start early. The key variable is how many years of growth you have. Someone who saves aggressively in their 20s and early 30s can hit Coast FIRE much earlier than someone who starts in their 40s — because 30+ years of 7% compounding turns $100K into roughly $760K. Example: a 28-year-old with $80K invested has about 37 years until 65. At 7% real return, that $80K grows to $986K without any additional contributions — already past Coast FIRE for a $40K/year lifestyle. Starting early is the single biggest lever.
How do taxes affect Coast FIRE calculations?
Simple Coast FIRE math ignores taxes, which can be a significant oversight. Withdrawals from traditional 401k/IRA are taxed as ordinary income in retirement. Withdrawals from Roth accounts are tax-free. Taxable brokerage withdrawals are taxed at long-term capital gains rates (0%, 15%, or 20%). For a more accurate Coast FIRE number, consider the effective tax rate on your planned withdrawals and gross up your annual expense number accordingly. If you need $60K after-tax and expect a 15% effective rate, your real target is $70K pre-tax, which increases your FIRE number from $1.5M to $1.75M.
What if my Coast FIRE number is still years away?
Keep saving aggressively — this is the accumulation phase. The savings rate during the accumulation phase matters more than investment returns in the early years. Focus on the big three: increase income (career growth, side hustles), decrease expenses (housing and transportation are usually the biggest), and invest the difference automatically. A 50% savings rate can get most people to Coast FIRE within 8-12 years from zero. The key is consistency — small monthly contributions over a long time horizon outperform large sporadic contributions over a short one.
Data sources: Trinity Study (Cooley, Hubbard, Walz 1998); William Bengen "Safe Withdrawal Rates" (1994); long-term historical S&P 500 returns (1928-2025) from NYU Stern / Damodaran dataset; Bogleheads wiki on safe withdrawal rates.
Last updated: April 2026. Coast FIRE is a framework, not a prediction. Actual returns will vary and may be lower than historical averages.
Disclaimer: This calculator provides estimates for educational purposes only and is not financial advice. Past performance does not guarantee future results. Consult a financial advisor before making retirement decisions.