Wiki link: Variable percentage withdrawal
Variable percentage withdrawal (VPW) is a withdrawal method that adapts to the retiree’s retirement horizon, asset allocation, and portfolio returns during retirement. It combines the best ideas of the constant-dollar, constant-percentage, and 1/N withdrawal methods to allow the retiree to spend most of the portfolio using return-adjusted withdrawals. By adapting withdrawals to market returns, VPW will never prematurely deplete the portfolio.
The VPW method uses a variable (increasing) percentage to determine withdrawals from a portfolio during retirement. Each year, the withdrawal is determined by multiplying that year’s percentage by the current portfolio balance at the time of withdrawal.
The VPW method and spreadsheets were collaboratively developed and improved by a group of Bogleheads®.
The VPW Accumulation And Retirement Worksheet calculates variable portfolio contributions, during accumulation, and variable portfolio withdrawals, during retirement, while taking into account current and future pensions with and without cost-of-living adjustments.
On-going discussion and support is in this Bogleheads® forum topic: Variable Percentage Withdrawal.