Rental Capitol Gains Taxes

[Robert Perkins]

Good Morning Bigger Pockets Faithfuls!

I found a great multiy family rental, it has 7 total units and I think I can get it at the right price. 

My remaining issue is the tax implications of owning the property, I have the property tax covered with the calculator but I am concerned about the capitol gains tax. The rentals will make approximately $4,375 per month but that will only produce a positive cash flow of roughly $700.... Will I have to pay capitol gains on the entire $4,375 per month or just the $700 per month. 

Any suggestions on where I can Learn more about this?

Cheers,

GettingaGrip