The application called Management of Costs of Dairy Activity (GERCAL) was developed in a language compatible with operating systems of mobile technologies (Android) and lends itself to: (1) recording of income, expenses, milk production and inventory goods of milk production systems; (2) estimated depreciation values of inventory assets, effective operating cost, total operating cost, total unit operating cost, gross margin, net margin, percentage share of revenue items and percentage share of components of effective operating cost. The GERCAL application was formatted to calculate costs according to the methodological proposal by Matsunaga et al. (1976), called the Total Operating Cost methodology. In this methodology, the Total Operating Cost corresponds to the sum of the Effective Operating Cost, Depreciation Cost and Family Labor Cost. The items that make up the Effective Operating Cost are divided into 14 groups, namely: food, pasture rent, fuel, miscellaneous expenses, financial expenses, labor charges, energy, hormones, sales taxes and contributions, artificial insemination, - contracted work, milking, sanitation and third-party services. In addition to this information, the application allows the sending of recorded data for the purpose of, once anonymized, mass analysis with the objective of elaborating subsidiary scientific studies, among others, of public policy guidelines for the dairy sector.