The application is designed to calculate the cost of power and energy losses in power transformers and autotransformers. It is designed to use the data of the following types of transformers: a two-winding transformer - voltage transformer having a secondary winding voltage; three-winding transformers - voltage transformer having two secondary windings: primary and secondary. Parameters for input: n - Number of parallel transformers (u.) Snom - Rated power transformer (kVA) Smax - Transformer