What investment formulas do I need for rental properties?

[Peyton LaBarbera]

I am overwhelmed by the number of different formulas that are out there for rental property investing and I don't want to overpack for lack of better words my investing formula arsenal so I would like to know what ones are the best to use and why

The ones I currently use include: COC, NOI (and NIAF), Cap rate, ROR, ROI, and IRR=

But I also have heard of NPV, 

I am also not including any "rule formulas" aka 1% and 50% as those are simply guidelines to follow and not complicated formulas

Let me know if I am missing any or don't even need to use some of the ones I am using

Thank you,

Peyton LaBarbera