What is a good rule of thumb everyone is using to calculate expenses on smaller multi family facility’s when doing a quick back of the napkin evaluation on a property (5-20 units)?

Be mindful here that you're expected to keep the property vacant, sanitary and in living condition while you wait. 

j/k The purchase price to monthly rent ratio passes my napkin test but you're missing a few very important expenses to analyze the deal properly. 

., the cash flow of course is well into the negative while you live there, and my napkin calculations tell me the numbers will still be tight, even after you move out.

I’m familiar with using the 50% rule as a napkin number, which includes more immediate things like upkeep, property management, and property taxes; but for the long term things like a roof, what do I do with that money?

Matt for napkin math first thing I like to do is look at the Median for the whole MSAso lets say KC the median price point for the entire area is 150k.. which is a WAG on my part but I bet its close in reality.I then know that homeowners are buying basically 130k and up and that landlords are buying 120k and below.. and then know that 30k or 40k is the cheapest area of town and will then by LOGIC and default have the worst tenants in the MSA.. now granted there can be some nice folks there but as general rule birds of a feather.And then I know that Higher end properties are going to rent for more.. and then we do know that its a rule of thumb that you must have 3X rent to qualify for a rental in most markets.. so we want our tenant to have enough for rent and enough to live on .So in my mind I would be looking much closer towards the MSA than I would be the cheapest home in an area.

With that being said, do you all out there use any sort of 'back of the napkin' estimates before you've gotten your contractor over there to see the property in person?  

@Gabe N. between the late payments, extra dog and total disregard for sanitary living conditions, there is no hope here.

We usually estimate 100 a month in taxes and 100 a month in insurance for a typical back of the napkin analysis on a SFR asset, but that’s not necessarily true in your area, and if the house was purchased for $65k.... well, I hear you.

The sanitary system needs to be filled all the way to the top fixture with water and let sit for 24 hours and inspected again.