Every assumption deserves a label.
Contribution rate, return, inflation, taxes, fees, time horizon, and withdrawal rules can all change the output. A good calculator makes those assumptions visible.
Run ranges before believing the result.
ConservativeLower return, higher inflation, higher fees.
BaseReasonable long-term planning case.
OptimisticUseful only if the downside still works.
Outputs are prompts, not advice.
A shortfall may mean saving more, spending less, changing goals, reviewing allocation, or learning more. It does not automatically mean taking more risk.