That is something you can do on a desktop computer and take lots of notes on.  

They even offer desktop appraisals, if the property qualifies for it. 

BPP has one on desktop and it's great, but need one on my phone. 

I have tried a few rental property calculators and I'm looking for recommendations of some easy to use that I could use on my phone or desktop.

It's not free, but QB Desktop is the way to go, IMO.

Even doing comp itself is sometimes vague because like I say, comps high and comps low has three to four standard deviation, in a one million home, the range could be from $850k to $1.3mil.and to make even thing more complicated even the same house that was sold for X price in March, same house could go to 0.98x by December due to seasonality aspect of neighborhood and supply-demand dynamics.From statistical perspective, zEstimate is good when there're lot of similar comps in the neighborhood with condensed price pattern (for example, if neighborhood price is ranging from 200k-250k ; but it would be all over the place if home price is too low or too high).Even professional desktop appraisl would face similar problem as well, so I would not blame Zillow/zEstimate. this is merely statistical issue.So you still need professional appraisal.But again if you ask three different appraisar, they would come with three different opinions LOL , it's the reality.

If anyone else knows of one please let us know.There are a number of desktop software solutions.

Quickbooks is a better option (QBO or Desktop). 

@Courtney OldrinBelow are some tips/suggestions when it comes to organization / bookkeeping.Accounting Software Recommendations - Quickbooks(Desktop), Quickbooks(Online), Stessa, XeroOnline Storage to save receipts recommendations- Google Drive, Dropbox, Apple DriveExcel - to save information such as tenant name, lease start date, current rent, etc

Which version are your looking for QuickBooks Desktop or QuickBooks Online?