Q. To calculate the monthly installment and figure how many months before you deplete your account, what is a reasonable rate of return to insert into the calculator? Or is there a better way to figure this out?
A. You’ve pointed out the problem that makes this calculator useless at best and dangerous at worst. Competently run Monte Carlo Simulation is needed to figure this out. Without that and some corresponding account management, you should consider using your funds to buy a fixed immediate annuity to provide lifetime income.