Portfolio Withdrawal Calculator
Calculate safe withdrawal amounts from your investment portfolio, how long it will last, or the portfolio size needed to sustain your desired retirement income.
All calculations happen in your browser. No data is sent anywhere.
How Much Can I Withdraw?
How Long Will It Last?
How Much Do I Need to Retire?
The 4% Rule & Withdrawal Math
The 4% Rule
A widely cited retirement guideline: withdraw 4% of your portfolio in year one, then adjust for inflation annually. Based on historical US stock/bond returns, this historically supported 30-year retirements. With a $1,000,000 portfolio, that means $40,000/year. This calculator generalises the rule for any return, duration, and withdrawal amount.
How the Math Works
The calculator uses the present-value-of-annuity formula with monthly compounding: PV = PMT × (1 − (1+r)^−n) / r, where r is the monthly return rate and n is months. To find duration, it solves for n using the closed-form formula: n = −ln(1 − V₀r/PMT) / ln(1+r). All inputs use annual rates converted to monthly for precision.
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Open calculator →FAQ
What is the 4% rule?
The 4% rule is a retirement guideline: withdraw 4% of your portfolio in year one, then adjust for inflation each year. Based on the Trinity Study using historical US stock and bond returns, this historically sustained 30-year retirements. It does not guarantee success in all market conditions, and lower withdrawal rates provide more safety margin.
How long will my portfolio last?
Duration depends on portfolio size, withdrawal amount, and investment return. If your withdrawal rate is below your portfolio's return rate, the portfolio theoretically lasts indefinitely (it grows faster than you spend). The "Find How Long" tab above calculates the exact duration based on your inputs.
How much do I need to retire?
A common rule of thumb is 25× annual expenses (the inverse of the 4% rule). For example, if you need $48,000/year, you need $1,200,000. The "Required Portfolio" tab calculates the exact amount for any return rate and retirement period. At 5% return over 30 years, roughly $732,000 supports $48,000/year.
What return rate should I use?
Use a realistic long-term portfolio return. A 60/40 stock/bond portfolio has historically returned around 6–8% before inflation. After inflation, returns are typically 3–5%. Using a more conservative estimate (4–5%) provides a larger safety margin. The calculator uses the rate as a nominal annual return, compounded monthly.