Cost Basis of Converted Property

[Peter Vanzino]

I have a property that converted from personal use to a rental property in 2017. For depreciation on my taxes, the cost basis was defined with the fair market value at time of conversion. I am considering selling now, would the capital gain be based on the FMV in 2017 or the adjusted cost basis (purchase price + capital improvements - depreciation)? I think it is the adjusted cost basis, if that is correct, does it matter that this hasn't been defined in my tax returns previously?