Portfolio Drawdown Calculator

This portfolio drawdown calculator helps individuals and financial planners estimate how long a retirement or investment portfolio will last under regular withdrawals. It factors in starting balance, withdrawal rate, expected returns, and inflation to model real-world drawdown scenarios. Use it to stress-test your withdrawal strategy against market fluctuations and changing expenses.
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Portfolio Drawdown Calculator

Model how long your investment portfolio will last under regular withdrawals

Enter dollar amount for fixed withdrawals
Pre-tax, average annual return across all holdings
Only applies to fixed dollar withdrawals

How to Use This Tool

Follow these steps to generate accurate portfolio drawdown projections:

  1. Enter your starting portfolio balance (total value of all investment holdings).
  2. Select your withdrawal type: fixed annual dollar amount or percentage of your portfolio.
  3. Enter the corresponding withdrawal value (dollar amount or percentage).
  4. Input your expected average annual investment return (pre-tax) and projected annual inflation rate.
  5. Choose whether to adjust fixed withdrawals for inflation annually to maintain purchasing power.
  6. Select your calculation goal: years until portfolio depletion or ending balance after a set period.
  7. Click "Calculate Drawdown" to view detailed results, or "Reset" to clear all inputs.

Formula and Logic

This calculator models portfolio performance using annual compounding, with withdrawals subtracted at the start of each year after investment returns are applied. The core calculation follows this annual sequence:

  1. Current portfolio balance grows by the expected annual investment return rate.
  2. Withdrawal amount is calculated based on your selected type and inflation adjustment settings.
  3. Withdrawal is subtracted from the current balance, and totals are updated.

For fixed withdrawals, inflation adjustment increases the withdrawal amount by the annual inflation rate each year. For percentage-based withdrawals, the withdrawal equals the specified percentage of the current portfolio balance at the start of each year. Calculations cap at 100 years to avoid infinite loops for portfolios that grow faster than withdrawals.

Practical Notes

Keep these finance-specific considerations in mind when using this tool:

  • Expected returns are pre-tax and should reflect the weighted average return of all holdings in your portfolio.
  • Inflation erodes the purchasing power of fixed withdrawals over time, even if your portfolio balance remains stable.
  • Withdrawals from taxable brokerage accounts may be subject to capital gains or income tax, which this tool does not factor in.
  • Sequence of returns risk: early market downturns can deplete your portfolio faster than the same average return with steady market performance.
  • Rebalancing your portfolio annually to maintain your target asset allocation can help stabilize expected returns over time.

Why This Tool Is Useful

This tool serves multiple audiences in personal finance and financial planning:

  • Retirees can test whether their planned withdrawal rate will sustain their lifestyle for their expected lifespan.
  • Financial planners can model multiple scenarios for clients to demonstrate the impact of adjusting withdrawals, returns, or inflation.
  • Pre-retirees can stress-test their savings goals to ensure they are on track to fund their desired retirement timeline.
  • Anyone with a taxable or tax-advantaged investment portfolio can compare fixed vs. percentage-based withdrawal strategies.

Frequently Asked Questions

What is a safe withdrawal rate for most portfolios?

The traditional "4% rule" suggests withdrawing 4% of your starting portfolio balance annually, adjusted for inflation, which historically lasted 30 years in most market conditions. This tool lets you test higher or lower rates to match your risk tolerance and time horizon.

How does inflation affect my portfolio drawdown timeline?

Inflation reduces the purchasing power of your withdrawals over time. If you do not adjust fixed withdrawals for inflation, your standard of living will decrease as prices rise. Adjusting for inflation maintains your purchasing power but increases the total amount withdrawn each year, shortening your portfolio's lifespan.

Should I use fixed or percentage-based withdrawals?

Fixed withdrawals provide predictable annual income, making budgeting easier, but may leave you with a large remaining portfolio or deplete faster during high inflation. Percentage-based withdrawals adjust automatically with portfolio performance, so you withdraw less when markets are down, but your annual income will fluctuate with market conditions.

Additional Guidance

Use this tool as a starting point for your financial planning, not a substitute for personalized advice from a certified financial planner. Update your inputs annually to reflect changes in your portfolio balance, market conditions, or retirement timeline. Consider factoring in required minimum distributions (RMDs) for tax-advantaged accounts like 401(k)s or IRAs once you reach age 73. Diversifying your portfolio across asset classes (stocks, bonds, real estate) can help reduce risk and stabilize expected returns over long time horizons.