<p>Conducted review of methods of calculation of productivity of open-pit excavators and results of verification calculations shows that, there is no uniform method that counts constantly changing physical and mechanical properties of developed rocks, technological parameters of a face, design and force parameters of an excavator, probability of its no-failure operation, casual character of transport delivery, qualification of the excavator operator, climatic conditions. Calculation of productivity of open-pit excavators under specific mining and geological conditions is made for planning and rationing of excavation and loading machines, the choice and provision of transport and establishment of a rational mode of their operation. In the given conditions of open-cut mining, an excavator, productivity depends on many natural, mining-technological, and organizational factors, which are difficult to take into account and largely interact with the design parameters of open-pit excavators. In fact, most of the factors are probabilistic in nature. As a consequence, it is advisable to define new values of productivity for each individual case based on the cumulative account of changes of multifactorial conditions of operation and technical conditions of technologically connected equipment. In this regard, it is of interest to determine the value of productivity of quarry excavators with an account of the stated factors.</p>