How do you calculate the Business Portion of an asset sales price for the sale of a rental property? And where does the non-business portion of the sale get reported?

I bought a home in 2012, converted it to a rental property in 2015, and sold it in 2017. From the time I converted it, it remained a rental until it sold. Is the "Business Portion" of the asset sale 100%, or is it the % of time it was a rental from 2012-2017? If it's the latter, where do I record the remaining portion of the sale?