For kerosene and diesel systems, tank qualities must be estimated. KPI plays a significant role here. To assess or realize the profit in a refinery, engineers need to consider some critical parameters. The concept of key performance indicators (KPI) is an important technique to assess the progress toward the success and achievement of the refinery objectives. In the context of OM&S, KPI is measured monthly. It is known as several closed movements. This topic deals with the diesel rundown blender, kerosene rundown blender, open-loop KPI criteria, monthly KPI report, open-loop KPI for diesel and kerosene blenders, steps to improve KPI, the definition of KPI, parameters in the KPI technique, and benefits of KPI.