Model withdrawals separately from spending needs
This tool projects a portfolio under one constant nominal return and three withdrawal rules. Social Security, pension and other income are added to distributions. There is no spending target, so a positive balance does not establish that your income is adequate.
Enter a consistent dollar basis
The portfolio balance is current USD. Before retirement it grows without added contributions. Enter the first withdrawal and monthly outside income in retirement-start dollars. Fixed withdrawals and outside income increase with the chosen inflation rate during retirement. Real income divides each year’s total by cumulative inflation since retirement start.
Compare the rules precisely
Fixed withdrawals use the initial dollar amount adjusted for inflation. The percentage rule divides the initial amount by the projected balance at retirement, then applies that rate to each opening balance. Neither rule promises that desired living expenses are covered.
Simplified guardrails compare the current planned withdrawal rate with the initial rate. Above 120% of the initial rate the amount is cut 10%; below 80% it rises 10%. These are explicit illustrative parameters, not a validated safe-withdrawal recommendation or a full implementation of a named research strategy.
Check what the outputs mean
Withdrawals occur at the beginning of each modeled year; returns apply to the remaining balance. Withdrawals are capped at available assets. A funding shortfall means that year’s planned portfolio distribution could not be fully paid. It is distinct from depletion after an exactly funded withdrawal. Negative investment returns remain negative in totals.
Social Security timing is an input
SSA explains claiming ages and personalized benefit estimates. Changing the start age here changes timing only, not the entered benefit. There is no automated claiming-age adjustment, survivor calculation or benefit optimization. All outside income is assumed inflation-indexed; adjust your interpretation for a fixed pension.
Review omitted risks before making decisions
Taxes, fees, contribution limits, required distributions and sequence-of-returns risk are not modeled. A 4% starting withdrawal is an assumption, not a guarantee. Test alternative returns and horizons, and assess spending needs outside this tool.