Volt‑Ampere Reactive (VAR) is the standard unit of reactive power in alternating‑current (AC) systems, symbolized as “var” and often written with the uppercase “VAr” to distinguish it from the volt‑ampere (VA) of apparent power. It quantifies the portion of electricity that oscillates between source and load without performing useful work, reflecting the energy stored and released by inductive or capacitive components such as motors, transformers, and capacitors. Engineers and technicians use VAR measurements to calculate power factor, size reactive compensation equipment, and optimize energy efficiency in industrial, commercial, and residential installations. Understanding VAR is crucial for preventing overloads, reducing electricity costs, and ensuring reliable operation of power grids, making it a fundamental concept in both practical electrical engineering and scientific analysis of AC power systems.