Educational tool only — not financial advice. Past performance does not predict future results. By using this site you accept our Terms and Privacy Policy; consult a qualified professional before making financial decisions.

Contributions & Withdrawals

Start with a balance and add or remove a fixed dollar amount every month. We replay your plan through every real 30-year window in the data (1928–2021) and show the worst, median, and best outcomes — no assumed return rate.

Historical backtests for education only — not investment advice; past performance does not guarantee future results.

Parameters
$
$
%
On = the monthly amount rises with actual historical inflation. Off = the same dollar figure every month. Results below stay in nominal dollars in either mode.
How to read this

Withdraw: a trial fails if the balance hits $0 before the end. The failure rate counts how many historical windows ran out.

Contribute: you only add money, so a trial never runs out — the range shows how different market histories grow the same plan.

Dollar basis: the chart and ending-balance summary use nominal dollars. The inflation switch changes the monthly cash flow itself; it is not a second display setting.