What do the best and the worst case mean?
The point
Three curves, three assumptions. None of them is a probability.
The base case takes your return. The best case takes your return plus the variance every year, the worst case your return minus it, for the whole period.
That makes the two outer curves useful as a range to think in, and useless as a forecast. Set the variance to zero and all three fall into one.
7.0 %
± 3.0 %
Best case
US$67,275
10.0 %
Base case
US$38,697
7.0 %
Worst case
US$21,911
4.0 %
Between best and worst: US$45,364
Best caseBase caseWorst case
How to read this in the simulator
The three tiles above the chart are these three cases. The variance is the field you set yourself; in the free version the two outer ones stay locked.
What the figure does not say
Nothing in it says how likely any of the three is. The best case is not an upper limit and the worst case not a lower one, they are two other assumptions.
Education, not advice. Disclaimer