Coast FIRE vs Fat FIRE vs Lean FIRE 2027 Comparison Calculator
Compare four major FIRE models side-by-side: Lean FIRE (minimalist), Coast FIRE (let compounding work), Regular FIRE (4% rule), and Fat FIRE (high-spending early retirement). Find which model fits your spending level, timeline, and risk tolerance for 2027.
The Four Main FIRE Models in 2027
The FIRE (Financial Independence Retire Early) movement splits into distinct sub-strategies based on spending level and timing. Lean FIRE retires on $30K–$50K/year through extreme frugality. Regular FIRE targets the classic 4% Trinity Study rule at $50K–$80K/year. Fat FIRE retires comfortably or luxuriously at $100K+/year. Coast FIRE achieves enough savings to STOP contributing — letting compounding alone reach traditional retirement age. Barista FIRE retires from full-time work but maintains a part-time gig for healthcare and some income. Each model implies different savings rates, timelines, and lifestyle trade-offs. Source: Mr. Money Mustache, ChooseFI, Bigger Pockets Money. Last updated: May 2026.
FI Number by Model: 25x vs 33x Rule
| Model | Multiplier | $50K Spending Target | SWR Implied |
|---|---|---|---|
| Lean FIRE | 25x | $1.25M | 4.0% |
| Regular FIRE | 25x | $1.25M | 4.0% |
| Fat FIRE | 33x | $1.65M | 3.0% |
| Coast FIRE | varies | Coast # at age 30 | 4.0% later |
| Barista FIRE | 12.5x | $625K | 4.0% on half |
Coast FIRE: The Lazy Path to FI
Coast FIRE is unique: it's the savings number you need today to never save another dollar and still hit traditional FI by age 65. The formula: Coast # = Target FI / (1 + return)^years_to_65. Example: $1.5M FI target, age 30, 7% real return, 35 years to 65. Coast # = $1.5M / (1.07)^35 = $140K. Save $140K by 30 and you can take a sabbatical or pivot to lower-paid passion work — your existing balance compounds to $1.5M by 65 without any new contributions. Coast FIRE lets you trade career stress for time freedom decades before traditional retirement.
Choosing Your Model: Spending Determines Everything
The model selection cascade: (1) Determine your real spending needs (not aspirational; track 12 months of actual spending). (2) Add 20–30% buffer for healthcare (a major early-retirement risk), home repairs, and discretionary surge years. (3) Multiply by 25 (4% rule) or 33 (3% rule for ultra-conservative or 50+ year horizons). (4) Compare against current savings. If gap is large, consider Barista FIRE (part-time work covers half). If small, consider Coast FIRE (stop saving, let compounding finish). Most successful early retirees pursue Regular or Fat FIRE because Lean's frugality is hard to sustain after 50+ years.