Finance
FIRE Number
Updated 2025-12-07
Definition
The investment balance required to retire and live on passive withdrawals, following the Financial Independence, Retire Early movement. The standard formula is annual expenses × 25, derived from the 4% safe withdrawal rate identified in the 1998 Trinity Study. A household that spends $60,000 per year needs $1.5M to hit its FIRE number. Lean FIRE targets bare-bones expenses; Fat FIRE assumes a comfortable lifestyle; Coast FIRE defines the balance at which existing investments will grow to the full FIRE number by traditional retirement age without any further contributions.
Primary source: Center for Retirement Research at Boston College
Related Calculators
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