I was curious so took a look at that calculator. I cannot recommend it at all. It has several serious faults.
A) Default is that your retirement spending is equal to your working income minus savings. That may be true, but they should guide you to the deltas. How about Health Care?
B) It looks like a static X% increase assumed for investments? What about inflation? Hard to tell w/o details. Ahh OK, I clicked the tab - they 'buy' a COLAd annuity with your funds, so I guess that is accounted for, IF you are comfortable with an annuity.
C) It just asks if you/spouse will receive SS - no question as to how much? How can they assume what you are entitled to on one year's salary?
D) It does not ask you when
you collect your pension, and if it is COLA'd. This can make a 4x delta in its true value. That is HUGE.
I really don't like MonteCarlo analysis for this. I like the fact that FIRECALC captures the real historic interaction between stocks, bonds and inflation.
Id suggest that you get the numbers together and enter them in FIRECALC, and ask for help if you need it. It seems pretty simple to me, though some of the entries can be a bit confusing until you understand what they are looking for. Far better than GIGO for such an important decision.