Early Retirement MathFIRE Calculators
FIRE Calculator Suite

FIRE Number Calculator

How much do you need to retire early? Enter your numbers below to find your FIRE target, see how long it will take, and visualize your path to financial independence.

How much you plan to spend per year in retirement
Total invested assets today
How much you save and invest each year
Nominal annual return before inflation (e.g. 7 for the S&P 500 long-term average)

Your FIRE Number

$1,000,000

at 4.0% safe withdrawal rate

10% saved$100,000 / $1,000,000
Years to FIRE
23
Monthly Savings Needed
$1,587
Real Return
4.4%
FIRE Year
2049

Portfolio Projection

How it works

Methodology

Your FIRE number equals your planned annual expenses divided by your safe withdrawal rate. This is the portfolio size at which investment returns can cover your spending indefinitely.

The years to FIRE projection uses compound growth: each year, your portfolio grows by the real return rate (nominal return minus inflation), then your annual contributions are added. The projection stops when your portfolio reaches the FIRE number.

The chart shows your portfolio split into two components: cumulative contributions (what you saved) and cumulative investment growth (what the market earned for you). The dashed line marks your FIRE target. The crossover point — where growth exceeds contributions — is when compounding starts doing the heavy lifting.

All calculations run entirely in your browser. No data is sent to any server.

Common questions

FAQ

What is a FIRE number?

Your FIRE number is the total investment portfolio needed to sustain your annual spending indefinitely through withdrawals. It is calculated by dividing your annual expenses by your chosen safe withdrawal rate. For example, $40,000 in annual expenses at a 4% withdrawal rate means a FIRE number of $1,000,000.

What is a safe withdrawal rate?

The safe withdrawal rate (SWR) is the percentage of your portfolio you withdraw each year in retirement. The '4% rule' is based on the Trinity Study, which found that a 4% initial withdrawal (adjusted for inflation) survived 30 years in most historical periods. For early retirees with 40-60 year horizons, many use 3.25%-3.5% for additional safety.

How does inflation affect my FIRE number?

Inflation increases the cost of living over time, which means you need a larger portfolio to maintain the same purchasing power. This calculator uses a 'real return' — your nominal investment return minus inflation — to project your portfolio growth in today's dollars. A 7% nominal return with 2.5% inflation gives roughly a 4.4% real return.

Should I use 4% or a lower withdrawal rate?

The 4% rule was designed for a 30-year retirement. If you plan to retire in your 30s or 40s, your portfolio needs to last 50-60 years. Research from the FIRE community and updated Trinity Study analysis suggest 3.25%-3.5% is more appropriate for these longer time horizons. Use the withdrawal rate slider in advanced settings to see how this changes your FIRE number.

Does this calculator account for taxes?

This version uses pre-tax assumptions. In practice, your effective withdrawal rate depends on your account types (Traditional IRA, Roth IRA, taxable brokerage) and tax bracket. For tax-aware withdrawal planning, see our Roth Conversion Ladder Calculator (coming soon).

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