Systems, program product, and methods to estimate and manage flowing fluid characteristics of a fluid stream flowing through a pipeline in real-time, are provided. A system can include a vertically oriented extent of a pipeline for transporting crude oil, a pair of spaced vertically apart sensors or sensor assemblies connected to a bypass line interfaced with or positioned across the vertically oriented extent of the pipeline to obtain pressure and temperature readings of the crude oil flowing through the pipeline, a controller in communication with the pair of sensors or sensor assemblies, and crude oil analysis and management program product stored in the memory of the controller and adapted to determine or estimate density, specific gravity, and API gravity of the crude oil to thereby manage flowing fluid characteristics of the crude oil.