What is a FIRE number and how is it calculated?

Your FIRE number is the total invested net worth needed to live indefinitely off passive returns. It is calculated by dividing annual expenses by your safe withdrawal rate (e.g., $40,000 / 0.04 = $1,000,000).

What is the 4% Safe Withdrawal Rate (SWR)?

Originating from the landmark Trinity Study, the 4% rule suggests that withdrawing 4% of an investment portfolio in year one, adjusted annually for inflation, has historically lasted at least 30 years in 95% of market conditions.

What is the difference between Lean FIRE and Fat FIRE?

Lean FIRE covers only core essential survival expenses (typically 75% of current expenses), while Fat FIRE accommodates a lavish lifestyle with frequent travel and luxury spending (135%+ of baseline expenses).

Why is savings rate more important than income for early retirement?

A higher savings rate works twofold: it accelerates portfolio accumulation while simultaneously lowering the annual expense target needed to sustain your lifestyle in retirement.

Are my income and net worth details tracked or stored?

No. The calculator executes 100% inside your client-side browser without logging, tracking, or network transmission.

FIRE Calculator (Financial Independence)

Calculate your FIRE number, Lean FIRE, Fat FIRE, and exact years until financial independence and early retirement.

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Current Age

Current Net Worth ($)

Annual Take-Home Pay ($)

Annual Living Expenses ($)

Investment Return (%)

Safe Withdrawal Rate (%)

Expected Inflation (%)

Financial Independence Horizon

Target FIRE Number$1,125,000Generates $3,750 / month perpetual passive income

Years to Financial Freedom14.2 YearsRetire comfortably at age 43.2

Savings Rate50%

Annual Savings$45,000

Lean FIRE Target$843,750

Fat FIRE Target$1,518,750

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About FIRE Calculator (Financial Independence)

Aspiring to retire early and escape the 9-to-5 grind? The FIRE Calculator computes your financial independence number using the proven 4% rule (Trinity Study) and Fisher real-return compounding. Enter your current net worth, annual take-home pay, and living expenses to discover your exact savings rate, retirement age, and countdown in years to Lean FIRE, Regular FIRE, and Fat FIRE.

How to use FIRE Calculator (Financial Independence)

Input your current age and existing invested net worth.
Enter your annual take-home earnings and living expenses.
Fine-tune your expected investment return rate, safe withdrawal rate (typically 3.5% to 4%), and inflation.
View your target FIRE number, savings rate percentage, and years remaining until retirement.

Key features

Calculates regular FIRE (25x expenses), Lean FIRE (budget), and Fat FIRE (luxury)
Accounts for inflation adjustments via Fisher real-return compounding
Determines monthly perpetual passive income generated by your portfolio
Provides instant scenario buttons for early career, mid career, and sprint phases
100% private financial analysis — all calculations occur locally in your browser

Frequently asked questions

What is a FIRE number and how is it calculated?: Your FIRE number is the total invested net worth needed to live indefinitely off passive returns. It is calculated by dividing annual expenses by your safe withdrawal rate (e.g., $40,000 / 0.04 = $1,000,000).
What is the 4% Safe Withdrawal Rate (SWR)?: Originating from the landmark Trinity Study, the 4% rule suggests that withdrawing 4% of an investment portfolio in year one, adjusted annually for inflation, has historically lasted at least 30 years in 95% of market conditions.
What is the difference between Lean FIRE and Fat FIRE?: Lean FIRE covers only core essential survival expenses (typically 75% of current expenses), while Fat FIRE accommodates a lavish lifestyle with frequent travel and luxury spending (135%+ of baseline expenses).
Why is savings rate more important than income for early retirement?: A higher savings rate works twofold: it accelerates portfolio accumulation while simultaneously lowering the annual expense target needed to sustain your lifestyle in retirement.
Are my income and net worth details tracked or stored?: No. The calculator executes 100% inside your client-side browser without logging, tracking, or network transmission.