What-If Quick Calculator
The What-If Quick Calculator is a fast, interactive way to explore a question without running a full simulation. Change one input and the answer updates instantly — handy for a quick gut-check before you commit to a full run.
Not to be confused with the what-if recipes. Those recipes use the full Monte Carlo engine and the Compare tab for real decisions. This calculator is a single, instant, no-randomness estimate. Different tools for different moments.
What you can adjust
Pick what to vary from the Variable menu, then enter how far to move it in the Change box — the estimate updates instantly, showing your baseline against that single change. You choose how far to move it (the box takes a percentage, a number of years, or a dollar amount, depending on the variable):
- Stock return, bond return, and inflation — shift the assumed annual rates up or down
- Withdrawal target — scale your monthly spending target
- Retirement year — retire earlier or later
- Starting balances — scale today’s account balances
- Monthly contributions — scale your pre-retirement saving rate
- Social Security claim age and RMD timing — test those decisions too
You explore one dimension at a time — it’s a single, deterministic baseline-vs-one-change comparison. To combine several changes at once and weigh the full range of outcomes, use a full simulation and the Compare tab.
How to read it — and its limits
Because there’s no randomness, the calculator produces a single trajectory, not a range. That makes it fast, but it means it’s directional guidance only:
- ✅ Good for: "If stocks return 1% less, roughly which way and how much does my ending balance move?"
- ❌ Not a substitute for: judging whether your plan is safe. Safety lives in the full distribution — the P10 outcomes, the shortfall and ruin probabilities — which only a full Monte Carlo run shows.
Use the Quick Calculator to explore and build intuition; run the full simulation when you’re making an actual decision. See Understanding your results for why the range matters.
RetireRange is for educational and planning purposes only and is not financial, tax, or investment advice. The Quick Calculator is a single deterministic estimate, not a prediction. Consult a qualified financial planner for advice specific to your situation. See Limitations.