12 unit Building Valuation

[James Syed]

Hello BP Members, 

I am interested in purchasing this 12 unit building and would appreciate if members could assist me with purchase price. It's an off market property and Seller has passed away and his family doesn't have any p&l for me. What I have is:

12 units @650 a unit

$12,000 taxes

Lawn care, trash, water and sewer paid by the landlord

Property management in this area is 10%

Electric is paid by the tenants 

Year Built is 1950 or so

That is all what I have been given. They are asking $630,000. 

I use biggerpockets calc when I have all the numbers, but in this case, I don't. 

I would appreciate if BP members could assist with purchase price, may be some formula / rule of thumb, etc.