What Is FIRE?
Financial Independence, Retire Early (FIRE) is the point at which your invested assets generate enough passive income to cover your living expenses indefinitely — without needing to work. Once you reach FIRE, work becomes optional.
The core principle: if you have 25 times your annual expenses invested, a 4% annual withdrawal rate has historically sustained a portfolio for 30+ years. Your FIRE number is the target portfolio value that makes this possible.
The Formulas
FIRE Number = Annual Retirement Spending ÷ Safe Withdrawal Rate
Annual Savings = Take-Home Income − Annual Spending
Savings Rate = Annual Savings ÷ Take-Home Income × 100
Real Return = Investment Return − Inflation Rate
This calculator uses the real return rate so all values are in today's purchasing power. Income grows annually at your income growth rate. The projection runs year by year, compounding the portfolio and incrementing income each year.
Lean FIRE, FIRE, and Fat FIRE
Lean FIRE means retiring on 25% less than your current spending — requires less capital but leaves limited margin. Fat FIRE is retiring on 50% more — comfortable, with significant discretionary room. Your FIRE is based on your exact retirement spending estimate.
The 4% Rule
The 4% safe withdrawal rate comes from the Trinity Study (1998), which found that withdrawing 4% annually had a very high success rate over 30-year retirements with a balanced portfolio. For early retirees with 40+ year horizons, some planners use 3% or 3,5%. Use the SWR slider to see the impact on your FIRE number.
Frequently Asked Questions
What should I include in current invested net worth?+
Include pension pots, ISAs, brokerage accounts, ETF holdings, index funds, and savings accounts that are invested or earning a return. Do not include your emergency fund as an investable asset, and exclude home equity unless you plan to sell your home and rent in retirement. The calculator works best with assets that will compound at market rates over time.
Why use real return instead of nominal?+
Using the real return (nominal return minus inflation) means all values are in today's purchasing power. You enter your retirement spending in today's money, and the projection shows what that buys in real terms — without separately inflating future targets. A 7% nominal return with 2,5% inflation gives a 4,5% real return. This is the cleanest approach for long-term FIRE planning.
How does savings rate affect my FIRE date?+
Savings rate is the single most powerful lever. At 10% savings rate, FIRE typically takes 40+ years. At 25% it takes around 30 years. At 50% roughly 17 years. At 75% it can take under 10 years. A high savings rate does two things simultaneously: it accelerates portfolio growth and reduces how much you need at retirement — because a lower-cost lifestyle means a smaller FIRE number.
Does FIRE work in the Netherlands or Europe?+
Yes, but with country-specific adjustments. In the Netherlands, Box 3 wealth tax applies annually to your investment portfolio at 36% on a 5,88% fictitious return (2026), reducing effective returns. State pension (AOW) from age 67 reduces how much you need to withdraw in later years. Belgian investors face a new 10% capital gains tax from 2026. UK investors benefit from ISA sheltering. Adjust your return rate downward to account for the tax drag on your specific portfolio and country.
What is a realistic investment return rate to use?+
A globally diversified equity portfolio has historically returned 7–8% nominal annually over long periods. After 2,5% inflation, that gives a 4,5–5,5% real return. The calculator defaults to 7% nominal and 2,5% inflation (4,5% real). Being conservative on return assumptions is wise. For European investors after wealth taxes or CGT, an after-tax real return of 3,5–4,5% is often more realistic — use the slider to model this.