Reviewed by David Chen, CFA. Updated on December 13, 2025.
Determine the crucial milestone for your financial independence journey. The FIRE Number Calculator estimates the total portfolio value you need to safely retire, based on your expected annual spending and chosen Safe Withdrawal Rate (SWR).
FIRE Number Calculator
Enter at least two values to calculate the missing one.
Calculation Steps
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FIRE Number Calculator Formula
The core formula used for the FIRE Number is derived from the 4% Rule:
FIRE Number = Annual Expenses / Safe Withdrawal Rate (SWR)
Variables Explained
- Target Annual Expenses: The estimated amount of money you will need to spend annually in retirement. This is the cornerstone of the FIRE calculation.
- Safe Withdrawal Rate (SWR): The percentage of your total portfolio you can withdraw each year without running out of money, typically 4% (25x expenses).
- Goal FIRE Number: The total size of the investment portfolio required to sustain your Annual Expenses at the chosen SWR.
Related Financial Calculators
Explore these related tools to refine your path to financial independence:
- Annualized Return Calculator
- Compound Interest Calculator
- Retirement Savings Calculator
- Net Worth Tracker
What is the FIRE Number?
The FIRE Number is the absolute total net worth required to declare yourself financially independent, meaning your passive investment income can cover your annual living expenses. It is directly based on the “4% Rule,” which posits that withdrawing 4% of your total portfolio value in the first year of retirement (adjusted for inflation thereafter) provides a very high probability of your money lasting for 30 years.
To put it simply, the FIRE Number is usually calculated as 25 times your desired annual expenses. For example, if you need $40,000 per year, your FIRE number would be $1,000,000 ($40,000 / 0.04). This number acts as your primary financial goal, giving you a clear, measurable target for your savings and investment strategy.
How to Calculate FIRE Number (Example)
A step-by-step guide to calculating the required portfolio value (FIRE Number):
- Determine Annual Expenses: Calculate your expected annual spending. For this example, let’s assume $60,000.
- Choose the Safe Withdrawal Rate (SWR): Select a rate. The most common is 4% (0.04).
- Apply the Formula: Divide your Annual Expenses by the SWR (as a decimal).
- Solve: $60,000 / 0.04 = $1,500,000.
- Result: Your required FIRE Number is $1,500,000.
Frequently Asked Questions (FAQ)
Is the 4% Safe Withdrawal Rate guaranteed?
No. The 4% Rule is based on historical market data (the Trinity Study) and provides a high probability of success over a 30-year period. However, market conditions, sequence of returns risk, and inflation can impact its success. Many advisors suggest using a slightly more conservative rate, like 3.5%, for a higher margin of safety.
Why do I need to enter my Annual Expenses?
Your annual expenses determine the size of the portfolio required. If you spend less, your FIRE number is lower, making it easier to reach financial independence sooner.
What is the difference between FIRE and traditional retirement?
FIRE generally aims for a much younger retirement age (often in your 30s or 40s) and relies heavily on aggressive saving and investing, using the Safe Withdrawal Rate calculation as the target benchmark.
Can I solve for my ideal Annual Expenses using this calculator?
Yes. If you know your current portfolio size (Goal FIRE Number) and a Safe Withdrawal Rate, the calculator can work backward to show you the maximum sustainable annual expenses you can afford in retirement.