A new tool for hydrokinetic energy potential assessment in rivers—HYDROKAL, which stands for a “hydrokinetic calculator”—is presented. This tool was developed in the Fortran 90 programming language as an external module for the CCHE2D application, an existing two-dimensional hydrodynamic numerical model developed at the National Center for Computational Hydroscience and Engineering, University of Mississippi. Velocity outputs generated by the CCHE2D model are used by HYDROKAL to compute the instantaneous power density, an essential element in calculating the hydrokinetic power of a river reach. The tool includes a user-defined efficiency factor to account for turbine efficiency, which is fundamental for estimating the energy that could be harvested from the river. For each river cross section along the computational domain, maximum velocity and specific discharge are identified to assist in estimating the stability of the river reach and, thus, the feasibility of installing an in-stream turbine. A Python script was also developed to export the results from HYDROKAL to CCHE2D. HYDROKAL is applied to a reach of the Tanana River at Nenana, Alaska, USA.