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Detailed Instructions: Safe Withdrawal Rate Calculator

Why use this calculator?

To simulate and compare advanced withdrawal strategies like Variable Withdrawal Strategies (VWS) against rigid Fixed Withdrawal strategies. It allows testing of "guardrails" (caps and floors) to see how they stabilize income and preserve capital. (Note: Simulations use inflation-adjusted "Real Dollars")

How to use it

Configure the Initial Balance and Base SWR. Then tune the strategy parameters: "SWR Adjustment Factor" (0 for Fixed, near 0 for % of Portfolio, ~50 for Variable), Change Caps (limits on income fluctuation), and Withdrawal Floor.

Example Inputs

Try these inputs to interpret the results correctly:

Parameter Example Value Description
Initial Balance ($) $1,000,000 Starting portfolio value.
Safe Withdrawal Rate (percentage) 5.0% Base Safe Withdrawal Rate percentage.
SWR Adjustment Factor (%) 50 (for VWS) Adjustment factor:
  • 0 for Fixed Withdrawal
  • ~0 for % of Portfolio (I.E. 0.001, as adjusting by near zero is about a constant percentage of portfolio)
  • > 0 for Variable Withdrawal Strategy (VWS - 50 means the withdrawal amount changes by 50% of change in portfolio return. I.E. if portfolio returns 10%, withdrawal amount increases by 5%)
Max Annual Increase (%) 5% Limits on how much the withdrawal amount can increase in a single year (VWS only).
Max Annual Decrease (%) 2.5% Limits on how much the withdrawal amount can decrease in a single year (VWS only).
Withdrawal Floor (%) 90% Minimum income floor as a percentage of the initial withdrawal amount (VWS only).
Retirement Duration (Years) 30 Length of retirement in years.
Real Return (%) 5.8% Average annual investment return (inflation-adjusted).
Standard Deviation (%) 6.1% Volatility of annual returns.
Note on Real vs. Nominal Dollars: Simulations use "Real Dollars" (inflation-adjusted). This means a 0% return maintains purchasing power, while positive returns approximate growth above inflation.

Example Output

Fixed Withdrawal Strategy (4% SWR)

Fixed Withdrawal Strategy (4% SWR)

Variable Withdrawal Strategy (5% SWR, VWS)

Variable Withdrawal Strategy (5% SWR, VWS)

Variable Withdrawal Strategy (5% SWR, VWS) - Final Balance Histogram

Variable Withdrawal Strategy (5% SWR, VWS) - Final Balance Histogram

Variable Withdrawal Strategy (5% SWR, VWS) - Withdrawal Amount Box Plot

Variable Withdrawal Strategy (5% SWR, VWS) - Withdrawal Amount Box Plot