Pretty slick, and I like how you keep it really simple. While this calculator is pretty much perfect in my mind for retirement calculations (
http://www.flexibleretirementplanner.co ... unch-page/), it is not nearly as accessible to the average person.
However, I second bulgari's comment on safe withdrawal rates. Two components are currently missing without it:
1. standard deviations - while, for example, 8% might be a reasonable return - 8% with 0 standard deviation is, not which is what would be necessary to sustain an 8% withdrawal rate
2. expenses need to keep up with inflation - though i guess you could think of all numbers including the return as inflation adjusted numbers if you wanted to
If you wanted to still keep it really simple, but more realistic I suggest two things:
1) assuming a 3% inflation adjusted safe withdrawal rate in retirement in your calculation, not the return rate entered.
2) either:
a) assume an inflation of 2.5% or something (you pick the number) and automatically adjust the monthly income for inflation (you should probably then put a note that it is today's dollars)
or
b) make some comment that the return entered should be after inflation and savings should increase with inflation or something like that
You could then have an advanced button that when you click creates more options and lets you adjust these numbers
Also, I suggest making the sliders a bigger range of numbers.
