Leave retirement spending blank to use your current expenses. Coast target age is when your savings would reach the full FIRE number on their own, with no further contributions.
Assumes constant real (inflation-adjusted) returns and steady expenses, contributions added yearly. It excludes taxes on withdrawals, Social Security and pensions. Real markets vary year to year — this is an educational projection, not advice.
Build the portfolio behind the number
A FIRE number is the target — the portfolio is how you get there. Create a free Kapio account to build a real index-fund and ETF portfolio, then stress-test it with a Monte-Carlo projection on 50+ years of actual returns.
Pressure-test your FIRE plan
Open the portfolio builder to model the real holdings behind your FIRE number and run a Monte-Carlo projection on actual historical returns.
What is FIRE?
FIRE stands for Financial Independence, Retire Early — a movement built on saving and investing aggressively so your portfolio can cover your living costs decades before the traditional retirement age. The idea is simple: once your investments generate enough to fund your expenses, a paycheck becomes optional. Most people pursuing FIRE save 50–70% of their income and reach independence in 10–20 years.
How the FIRE number is calculated
Your FIRE number is your annual expenses divided by your safe withdrawal rate. At the standard 4% rate that is 25 times your annual spending — $40,000 a year needs $1,000,000; $60,000 needs $1,500,000. The 4% figure comes from the Trinity Study, which found that withdrawing 4% of a stock-and-bond portfolio (adjusted for inflation) survived the large majority of historical 30-year periods.
Why savings rate matters more than income
In FIRE, savings rate is the single biggest lever. A high earner who spends everything is further from independence than a modest earner who saves 60%, because a higher savings rate both speeds up accumulation and lowers the target — living on less means you need less. Someone saving 50% of income reaches FIRE in roughly 17 years whether they earn $50,000 or $200,000. The timeline is driven by the ratio of saving to spending, not the absolute numbers.
What is coast FIRE?
Coast FIRE is the milestone where your existing investments, left untouched, would grow to your full FIRE number by your target age through compounding alone. Once you hit it, you no longer need to save — you just need to cover current expenses. That frees you to take a lower-paying but more fulfilling job, drop to part-time, or take risks without financial pressure. It is often the first major checkpoint on the journey.
Frequently asked questions
What savings rate do I need?
About 17 years to FIRE at a 50% savings rate, ~12 years at 60%, ~8 years at 70%. Even 30% gets you there in roughly 28 years. The relationship is not linear — it accelerates as the rate climbs.
Is the 4% rule safe for a 40-year retirement?
The original research covered 30 years. For 40–50 year horizons, many planners prefer a 3–3.5% withdrawal rate, which raises the FIRE number to 28–33x annual expenses. Flexible spending — less in down years, more in up years — also helps.
What return should I assume?
Use a real (inflation-adjusted) return. The 7% default reflects a diversified stock portfolio historically; 5–6% suits a stock-and-bond mix, and conservative planners use 4–5%. Don’t mix nominal returns with today’s-money expenses.
Does this include Social Security or pensions?
No — it models pure FIRE living off your portfolio. If you expect Social Security or a pension, subtract that from your retirement spending to see the adjusted target. Many treat it as a safety margin rather than relying on it.
What are the FIRE flavors?
Lean FIRE is a minimal budget; Fat FIRE is a comfortable one ($100k+/yr); Coast FIRE means your savings will reach the target without more contributions; Barista FIRE means a low-stress part-time job covers expenses while investments grow.