FIRE Calculator
A FIRE calculator (Financial Independence, Retire Early) determines your FIRE number—the amount needed to retire and live off investments. Once reached, work becomes optional.
FIRE Number Formula
FIRE Number = Annual Expenses × 25
This is based on the 4% safe withdrawal rate—you can withdraw 4% of your portfolio annually with low risk of running out over a 30-year retirement.
FIRE Number by Annual Expenses
| Annual Expenses | FIRE Number | Monthly at 4% |
|---|---|---|
| $30,000 | $750,000 | $2,500 |
| $40,000 | $1,000,000 | $3,333 |
| $50,000 | $1,250,000 | $4,167 |
| $60,000 | $1,500,000 | $5,000 |
| $80,000 | $2,000,000 | $6,667 |
| $100,000 | $2,500,000 | $8,333 |
FIRE Calculator Implementation
``javascript
function calculateFIRE(annualExpenses, currentSavings, annualSavings, returnRate) {
const fireNumber = annualExpenses * 25;
const gap = fireNumber - currentSavings;
if (gap <= 0) {
return { fireNumber, yearsToFIRE: 0, message: 'You have reached FIRE!' };
}
// Calculate years to FIRE
const r = returnRate / 100;
let years = 0;
let balance = currentSavings;
while (balance < fireNumber && years < 100) {
balance = balance * (1 + r) + annualSavings;
years++;
}
return {
fireNumber,
yearsToFIRE: years,
fireAge: null, // Add current age for this
monthlyWithdrawal: (fireNumber * 0.04 / 12).toFixed(2)
};
}
console.log(calculateFIRE(50000, 200000, 30000, 7));
// { fireNumber: 1250000, yearsToFIRE: 17 }
``
Accelerating FIRE
Reduce expenses (lower FIRE number), increase savings rate, or both. Many pursuing FIRE save 50-70% of income. Geographic arbitrage (low cost-of-living areas) can dramatically reduce your FIRE number.