I've taken a macro course and am more or less using those formulas (and translating them into basic examples in the grandparent). Present value only does so muc

I've taken a macro course and am more or less using those formulas (and translating them into basic examples in the grandparent). Present value only does so much lifting though, as my scope is a lot wider. Life is more complicated than that. You can't forget about different taxation treatment when comparing Roth/Traditional savings, savings outside of retirement accounts when applicable, etc. Excel also acts as a wrapper to allow for me to change my annual budget easily, my expected salary over time, expected inflation, etc and see the results. I'm not reinventing the wheel here, just making my own instance of the wheel. But the point remains: it's a heck of a lot more complex than this calculator. One of my "ideas to do if I had time" it to take that and make it into a "simpler" service that could actually be useful to people. I know most retirement helper companies try to do this but wow are they bad in my experience. The problem they are fighting of course is balancing the simplicity with the customization though, which I suspect is the crux. Still, to whoever finds that solution first, a pot of gold will follow.