Question 1

What is the FIRE number and how is it calculated?

Accepted Answer

Your FIRE number is the portfolio size needed to retire and live off investment returns indefinitely. The most common formula is: FIRE Number = Annual Expenses × 25. This comes from the 4% safe withdrawal rate (SWR) — if you withdraw 4% of your portfolio per year, it historically lasts 30+ years through market cycles. Example: $60,000/year in expenses → FIRE Number = $60,000 × 25 = $1,500,000. To be more conservative, some use a 3.5% SWR (multiply by ~28.6) or 3% SWR (multiply by 33).

Question 2

What is the difference between Lean FIRE, FIRE, and Fat FIRE?

Accepted Answer

Lean FIRE: retire on minimal spending ($25,000–$40,000/year), requires a FIRE number of $625K–$1M. FIRE (regular): typical middle-class lifestyle ($40,000–$80,000/year), FIRE number $1M–$2M. Fat FIRE: retire with a comfortable or luxurious lifestyle ($100,000+/year), FIRE number $2.5M+. Coast FIRE: stop contributing now and let existing savings compound to your FIRE number by traditional retirement age — no more saving needed. Barista FIRE: semi-retire with part-time work covering basic expenses.

Question 3

Is the 4% rule still valid in 2026?

Accepted Answer

The 4% rule comes from the Trinity Study (1998) which found 4% withdrawal survived all 30-year periods in US market history. Most financial planners still use it as a starting point. However, for early retirees needing 40–60 year portfolios, a 3–3.5% SWR is safer. Key considerations: (1) Sequence of returns risk — a market crash in year 1 of retirement is more damaging than later. (2) Flexibility matters — reducing withdrawals 10–15% in bad years dramatically improves survival rates. (3) Social Security income after 62–70 reduces withdrawal pressure significantly.

Question 4

How long does it take to reach FIRE?

Accepted Answer

Your savings rate is the biggest driver. With a 10% savings rate, you need about 40 years. With 25% savings rate: ~30 years. With 50% savings rate: ~17 years. With 75% savings rate: ~7 years. The math: years to FIRE depends on your current savings, expected return (typically 7% real after inflation), and the gap between your FIRE number and current savings. Higher savings rate both reduces the gap faster AND means you need less (because your expenses are lower, so your FIRE number is smaller).

Type	Annual Spend	FIRE Number (4%)	Best For
Lean FIRE	$25,000	$625,000	Frugal minimalists, low-cost areas
Regular FIRE	$50,000	$1,250,000	Middle-class lifestyle, moderate spending
Fat FIRE	$100,000	$2,500,000	Comfortable or luxurious retirement
Barista FIRE	$30,000 passive + part-time	$750,000+	Semi-retirement with part-time work
Coast FIRE	N/A — stop contributing	Varies by age	Let compounding do the work

Savings Rate	Years to FIRE	Example
10%	~40 years	$5K saved / $45K spent
20%	~33 years	$10K saved / $40K spent
30%	~28 years	$15K saved / $35K spent
40%	~22 years	$20K saved / $30K spent
50%	~17 years	$25K saved / $25K spent
60%	~13 years	$30K saved / $20K spent
70%	~9 years	$35K saved / $15K spent
80%	~6 years	$40K saved / $10K spent

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