Just google "rental property calculator", plenty of them exist including one from BiggerPockets itself: https://www.biggerpockets.com/rental-property-calculatorThe most difficult component to predict these days is the annual interest expense. 

@Brian Burke  just like all real estate in a bad down cycle nothing is immuned even though we see people all the time on BP say in a bad market rentals will get stronger.. but they just dont know what they dont know.seem many a syndicated deal go turtle up.. generally in bad economic times.. or just plain mis management or even fraud by sponser.and I predict since do it your self syndication is being taught like flipping houses.. the next 5 years are going to find many a deal with those who just bit off a little more than they can chew..

That usually translates into pretty severe negative cash flow predictions on the order of $500 to $1600+ per month.

Any online site could be used, and the results would be about the same.I looked up four recently rented properties on the MLS and compared the median Rentometer prediction to the actual rent.

Have you considered an open-ended real estate fund that offers predictable and stable income with a diversified portfolio of investments?

Frankly, I'd be pissed that the Seller's Agent contacted you about this WITHOUT showing you (a) how the calculations were completed with an explanation of how they arrived at the "overestimated" property tax credit and (b) the new and allegedly correct calculations with an explanation of how they arrived at the correct property tax credit.IF you were represented by an Agent in the transaction, the Seller's Agent should not have contacted you directly.In Illinois, if you were my Client, the Seller's Agent would never contact you if you had an attorney at closing.I don't mean to be rude but I hate it when people like this Agent makes a statement that you owe her Client $$$ but she can't give you the amount and she doesn't really know that you should actually pay it, which is why she hasn't explained it to you.Personally, I would email her back with an "email my agent" or "email the title company" message and then wait, so that you don't do all the work trying to find out what this is all about.AND don't agree to anything as there are a lot of variables involved, which will probably include the Seller predicting that a tax rate will change or the assessed value will change (perhaps not since I am unfamiliar with Texas property tax procedures). 

Generally, once you settle in, things get more predictable and stable.

The market for rentals is the strongest it's been since the 1960's and is predicted to remain strong for the next decade based on trends currently in-place.They will build a nice stream of income for you giving you the freedom to expand into other things.The main thing is to make sure you buy smart.  

Were  also exploring fractional sales advantages at the moment, which is showing far more predictable returns than whole ownership?  

A quick google search of "lima one capital reviews" could have predicted this outcome as likely.