IndieDev FIRETwenty-five times your spend
The 4% rule is the most quoted number in FIRE. It comes from the Trinity Study: a portfolio of 50–75% stocks, 25–50% bonds, withdrawing 4% of its starting value annually (adjusted for inflation), survived 30 years in 95%+ of historical periods.
Flip the equation and you get the FI number: 25 × annual expenses. Spend $40k/yr → need $1M. Spend $80k/yr → need $2M. The rule is brutally simple. The simplicity is also where it lies.
What the 4% rule actually says
The rule does not say "you can withdraw 4% forever." It says: take 4% of the starting balance in year one, then increase that dollar amount by inflation each year. Stock and bond returns do the rest.
It assumes a 30-year horizon. For a 35-year-old indie dev who hits FI early, 30 years isn't enough. The Bengen-equivalent for 50+ year horizons is closer to 3.3–3.5%.
The 25× number
| Annual spend | FI number (25×) | FI number (3.5%) |
|---|---|---|
| $30,000 | $750,000 | $857,000 |
| $50,000 | $1,250,000 | $1,429,000 |
| $80,000 | $2,000,000 | $2,286,000 |
| $120,000 | $3,000,000 | $3,429,000 |
The 3.5% column is for indie devs planning 40–50 years post-FI. Use it. The cost of being wrong on the high side is a few extra years of work. The cost of being wrong on the low side is going back to a job at 60.
Where the rule breaks for indie devs
Three places.
Sequence of returns. A 40% drawdown in your first five FI years can permanently impair the portfolio even if average returns are fine. The fix is a cash buffer and willingness to underspend during bad years.
Healthcare. The Trinity Study assumed retirees on Medicare. ACA marketplace plans for a self-employed couple in their 40s can run $1,500–$2,500/mo. Build that into your annual spend before you multiply.
Continued income. Most indie devs don't fully stop. App revenue, freelance, a half-built product — these flow regardless. Even $20k/yr of post-FI income reduces the required portfolio by $500k. That's a year or two of extra building, not five.
How to use it
Calculate your honest annual spend (last 12 months, not your aspirational budget). Multiply by 25 for a 30-year horizon, by 28–30 for early FIRE. That's your number.
Then ignore everything else. The number doesn't care about market predictions. It cares about your spend.
Ship. Stack. Live.