Running numbers and the unknown

[Josh Cohen]

Regarding "running numbers" on a property.... I'm new at this so bare with me..... I want to run numbers on numerous properties before pulling the trigger, as an exercise, so I am better prepared when I am ready. Unfortunately, I don't understand how to estimate potential repairs/rehab, and many of the known and unknown expenses that will arise? I have been on the BP calculator, but when I get to certain questionable items, I have no idea what to enter without getting false estimate. Is there a formula I can use? Thank you! Josh