FIRE Financial Independence Retire Early Cheat Sheet

Updated 2026-05-22

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FIRE (Financial Independence, Retire Early) is a personal finance movement built around the idea that aggressive saving and investing can free you from mandatory work decades ahead of the conventional retirement age. It grew from the Boglehead and frugality communities of the 1990s–2000s, gained mainstream visibility through bloggers like Mr. Money Mustache, and has since spawned dozens of specialized variants for different income levels and lifestyle goals. The central insight that makes FIRE tractable — and that most people miss — is that your savings rate, not your income, determines how long you must work: a household saving 50% of income needs roughly 17 years to retire regardless of absolute income, while one saving 10% needs over 50 years.

What This Cheat Sheet Covers

This topic spans 15 focused tables and 114 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.

Table 1: Core FIRE Concepts and DefinitionsTable 2: Types of FIRETable 3: The Savings Rate and FIRE MathTable 4: Tax-Advantaged Accounts for FIRETable 5: Early Access to Retirement Funds Before Age 59½Table 6: Withdrawal Strategies in RetirementTable 7: Sequence of Returns Risk and Asset AllocationTable 8: Healthcare Strategies Before MedicareTable 9: Tax Optimization Strategies for FIRETable 10: Budgeting Frameworks for FIRETable 11: Geographic Arbitrage and International FIRETable 12: Real Estate as a FIRE VehicleTable 13: Post-FIRE Psychology, Purpose, and IdentityTable 14: Common FIRE Myths and CriticismsTable 15: FIRE Communities and Key Resources

Table 1: Core FIRE Concepts and Definitions

Every FIRE journey begins with the same small set of foundational formulas and mental models. Understanding the 4% Rule, the 25x target, and the savings-rate math is the prerequisite for every other decision in the FIRE framework.

Concept	Example	Description
4% Rule (Safe Withdrawal Rate)	Spend $40,000/yr \to need$ 1,000,000 portfolio	Withdraw 4% of your portfolio in year 1, then adjust for inflation each year; originally validated on 30-year horizons by Bengen (1994).
Rule of 25 (25x Rule)	Annual expenses $50,000 \times 25 = FIRE number$ 1,250,000	The portfolio size that allows a 4% withdrawal rate; the direct mathematical inverse of the 4% Rule.
FIRE Number	`Annual expenses ÷ 0.04 = FIRE number`	Your personal portfolio target at which you can retire; recalculated whenever annual spending changes.
Savings Rate	Save $40,000 on$ 100,000 income → 40% rate	Percentage of income saved and invested; the single biggest lever on your retirement timeline.
Financial Independence (FI)	Portfolio covers all living expenses without employment	The point at which investment income can permanently replace a paycheck; "retire" is optional — many keep working by choice.

Table 1: Core FIRE Concepts and Definitions

Concept	Example	Description
4% Rule (Safe Withdrawal Rate)	Spend $40,000/yr \to need$ 1,000,000 portfolio	Withdraw 4% of your portfolio in year 1, then adjust for inflation each year; originally validated on 30-year horizons by Bengen (1994).
Rule of 25 (25x Rule)	Annual expenses $50,000 \times 25 = FIRE number$ 1,250,000	The portfolio size that allows a 4% withdrawal rate; the direct mathematical inverse of the 4% Rule.
FIRE Number	`Annual expenses ÷ 0.04 = FIRE number`	Your personal portfolio target at which you can retire; recalculated whenever annual spending changes.
Savings Rate	Save $40,000 on$ 100,000 income → 40% rate	Percentage of income saved and invested; the single biggest lever on your retirement timeline.
Financial Independence (FI)	Portfolio covers all living expenses without employment	The point at which investment income can permanently replace a paycheck; "retire" is optional — many keep working by choice.