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FIRE Calculator

Financial Independence, Retire Early. Enter your numbers — see the exact year you can stop working.

years
$
%
% of income you save+invest
$
$
%/yr
S&P 500 real return: ~7-8%
%
4% rule (Trinity Study)

How to Use This Calculator

When Can I Retire? tab

Enter your age, income, savings rate, and annual expenses. The calculator computes your FIRE number (how much you need) and simulates year-by-year growth to find the exact year your investments cover your expenses forever.

How Much Do I Need? tab

Set your desired annual spending in retirement and target retirement age. See the total nest egg needed and the monthly savings required to reach it from where you are today.

What If? tab

Enter an extra monthly savings amount. See how many years earlier you can retire. This is the most powerful tab — it shows that small changes ($200-500/month) can move your retirement date by 5-10 years.

The Formula

FIRE Number = Annual Expenses ÷ Withdrawal Rate (default 4%)
Years to FIRE = iterative simulation: (savings + annual contribution) × (1 + return) until ≥ FIRE Number

The key insight: savings rate affects both sides. Saving more increases contributions AND reduces your FIRE number (because you need less to live on). This is why savings rate is more powerful than investment returns.

Example

Alex & Jordan — Age 30, Combined Income $170K

Savings rate25%
Annual expenses$63,750
FIRE number$1,593,750
Retire atAge 52 (2048)

They switched to What If? and added $500/mo extra savings. Result: retire at 48 instead of 52. Four years of freedom for $500/month. They cancelled their second car (saving $800/mo) and moved their retirement date to age 46.

FAQ

The 4% rule comes from the Trinity Study: withdrawing 4% of your portfolio annually, adjusted for inflation, has a very low chance of depleting your savings over 30 years. It assumes a diversified portfolio. Some prefer 3.5% for extra safety.
At 10% savings rate: ~40 working years. At 25%: ~30 years. At 50%: ~17 years. At 75%: ~7 years. Higher savings rate both increases contributions AND lowers the target (you need less because you spend less).
The S&P 500 has returned ~10% nominally and ~7% after inflation over the past 100 years. The default 8% is between nominal and real returns. For conservative planning, try 6-7%. The What If tab lets you compare scenarios.
FIRE means work becomes optional, not forbidden. Many FIRE'd people do passion projects, consulting, or part-time work. Even a small income after FIRE dramatically reduces portfolio risk. The calculator shows the number where work is a choice, not a requirement.

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