Question 1

What is a FIRE number?

Accepted Answer

Your FIRE number (Financial Independence, Retire Early) is the investment portfolio size that can sustain your lifestyle indefinitely. It's calculated as annual expenses ÷ 0.04, based on the 4% safe withdrawal rate from the Trinity Study. At $50,000/year in expenses, your FIRE number is $1,250,000.

Question 2

What is the 4% rule for retirement?

Accepted Answer

The 4% rule states that a diversified portfolio can sustain withdrawals of 4% of its initial value (inflation-adjusted annually) for at least 30 years, based on historical US market data. It comes from the 1998 Trinity Study. Some researchers suggest 3–3.5% for longer retirements.

Question 3

How long does it take to reach financial independence?

Accepted Answer

Time to FI is primarily driven by savings rate. Saving 10% of income takes 40+ years; 25% takes about 32 years; 50% takes roughly 17 years; 75% can achieve FI in about 7 years. Investment returns also matter significantly.

Question 4

What is Coast FI?

Accepted Answer

Coast FI is the portfolio size at which you no longer need to add contributions — your investments will grow to your full FI number by traditional retirement age through market growth alone. It allows you to 'coast' by covering living expenses without building wealth aggressively.

Financial Independence Number Calculator