For the process of treating organic waste, rotary composters are frequently employed. The amount of energy used to move the organic waste is a crucial factor to consider when designing a composting machine and selecting an appropriate motor. Using a simplified model created by regression approximation from mechanical equations, the power for the movement of organic material can be expressed as a clear and specific function of the composter size, operational parameters (direction of the sun, humidity, etc.), and organic waste qualities. The effectiveness of this model is confirmed with experimental measurements on an industrial rotating composter, yielding satisfactory results and accuracy.