Financial Independence Number Calculator
Calculate your FI number based on annual expenses and withdrawal rate. See your current progress and how many years until you reach financial independence.
About this calculator
This calculator applies the '4% rule' popularized by the Trinity Study to turn your annual spending into a target portfolio size, then projects how long it will take to reach it. FI Number is Annual Expenses divided by the Safe Withdrawal Rate (expressed as a decimal) -- at the default 4% rate this is the familiar '25x annual expenses' shortcut, but raising the withdrawal rate lowers the FI Number because a higher assumed withdrawal percentage means a smaller portfolio can sustain the same spending. FI Number depends only on Annual Expenses and Safe Withdrawal Rate; Current Net Worth, Annual Savings, and Expected Annual Return have no effect on it at all -- they only affect how fast you get there, not the target itself.
Current Progress is simply Current Net Worth as a percentage of FI Number. Years to FI is computed by simulating monthly compounding of your current balance plus new monthly savings at the expected return, capped at 100 years if the target is unreachable within that horizon (which happens if you enter $0 Annual Savings with either $0 Expected Return or $0 Current Net Worth, since there is then no mechanism for the balance to grow at all). This tool doesn't model taxes on investment gains, changes to spending or income over time, sequence-of-return risk in early retirement, or the fact that markets don't return a smooth average every year -- the projected timeline assumes constant, predictable growth, which real portfolios never provide.
Financial Disclaimer
This calculator is for educational purposes only and does not constitute financial advice. Results are estimates based on the inputs provided. Consult a qualified financial advisor before making investment or financial planning decisions.
Inputs
Results
FI Number
$1,250,000.00
≈ 3 average U.S. homes
How to Use This Calculator
- Enter your annual living expenses — this is the core driver of your FI number.
- Set the safe withdrawal rate (4% is the standard starting point from the Trinity Study).
- Enter your current invested net worth (exclude home equity unless you plan to sell).
- Set your annual savings amount and expected return on investments.
- Review your FI number (25x annual expenses at 4% withdrawal), your current progress percentage, and years to financial independence.
How the result changes with Safe Withdrawal Rate
| Safe Withdrawal Rate | FI Number |
|---|---|
| 2% | $2,500,000.00 |
| 3% | $1,666,666.67 |
| 6% | $833,333.33 |
| 10% | $500,000.00 |
What each input means
- Annual Expenses
- Your total annual living expenses that investments need to cover in retirement.
- Safe Withdrawal Rate
- Percentage of portfolio withdrawn annually. The 4% rule is a common starting point.
- Current Net Worth
- Your current invested assets (exclude home equity unless you plan to sell).
- Annual Savings
- How much you save and invest per year.
- Expected Annual Return
- Expected average annual return on investments before inflation.
How this is calculated
Worked example, using the default values
- Identify Input Parameters5 parametersAnnual Expenses = 50000, Safe Withdrawal Rate = 4, Current Net Worth = 200000, Annual Savings = 30000, Expected Annual Return = 7 = 5 input(s) provided
- Calculate FI NumberFI Number1250000 = $1,250,000
- Calculate Current ProgressCurrent Progress16 = 16%
- Calculate Years to FIYears to FI14.1 = 14.1
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does raising the Safe Withdrawal Rate lower my FI Number?
FI Number is Annual Expenses divided by the withdrawal rate. A higher withdrawal rate means you're assuming you can safely take out a larger percentage of your portfolio each year, so a smaller total portfolio can still cover the same annual expenses -- that's why the target shrinks as the assumed rate rises, even though a higher withdrawal rate also carries more risk of depleting the portfolio.
Does increasing my Current Net Worth or Annual Savings change my FI Number target?
No. FI Number is calculated only from Annual Expenses and Safe Withdrawal Rate. Current Net Worth and Annual Savings affect Current Progress and Years to FI -- how close you are and how fast you're getting there -- but the target dollar amount itself doesn't move based on how much you've saved or how much you're saving.
What does it mean if Years to FI shows 100?
100 years is this calculator's ceiling for 'the target is not reachable within a realistic horizon' given the numbers entered -- it isn't a literal prediction that it will take exactly a century. This shows up specifically when Annual Savings is $0 and there's also no way for your current balance to grow (Expected Annual Return is 0%, or Current Net Worth is $0), since nothing in the model then increases your balance at all.
Is the 4% rule guaranteed to work for any withdrawal period?
No. The 4% figure comes from historical US market simulations (the Trinity Study) over roughly 30-year retirement horizons, and even in that research it wasn't a 100% success rate in every historical period. It's a widely used planning heuristic, not a guarantee, and results depend on your actual investment mix, sequence of market returns, and how long your retirement lasts.
Does this calculator account for taxes or inflation after I reach my FI Number?
No. It computes a target portfolio size and a savings timeline using constant nominal growth assumptions, but doesn't model capital gains or income taxes on withdrawals, inflation eroding your expenses over a multi-decade retirement, or year-to-year market volatility. Treat the outputs as a starting planning estimate, not a precise forecast.
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