Engineer Fat FIRE: High-Income Retirement Strategy
FIRE Number
$3.0M
Target Retirement Age
52
Years to FIRE
22
Monthly Savings Needed
$6K
Non-software engineers (mechanical, civil, electrical, chemical) earn $90,000–$150,000 at mid-career — lower than tech peers but often with stronger pension benefits at defense contractors, utilities, and government agencies. A defense contractor engineer with a 25-year defined benefit pension providing $45,000–$60,000/year in retirement dramatically reduces the personal portfolio needed for $120,000/year Fat FIRE spending. With pension covering $45,000–$60,000 of the target, the personal portfolio only needs to cover $60,000–$75,000/year — requiring $1.5M–$1.875M rather than $3M.
The engineering income trajectory matters for Fat FIRE. Starting at $85,000 and growing to $140,000+ over 20 years of experience, the typical engineer's income growth follows a long curve. Engineers who move into management ($150,000–$200,000+) or senior technical roles ($140,000–$180,000) significantly improve their Fat FIRE timeline. Geographic arbitrage — engineering in low-cost Texas, Tennessee, or the Southeast rather than California or New York — can add $15,000–$30,000 to effective annual savings through lower state taxes and cost of living.
Federal government engineers have the most complete Fat FIRE picture in engineering. FERS pension (1% of salary × years of service × high-3 average salary), TSP with 5% employer match and best-in-class expense ratios (0.048%), and a stable salary path provide a strong Fat FIRE foundation. A GS-14 engineer earning $140,000 after 25 years of federal service receives a pension of $35,000/year plus TSP of $800,000–$1,200,000 plus Social Security — a total Fat FIRE package that exceeds $3M in lifetime income.