The article deals with the urgency of adapting computational turbo-expander unit parameters techniques to the conditions of their application at gas distribution stations. Existing computational methods based on the use of air as the working medium yield incorrect data to determine the actual design parameters for operating conditions where the working medium is natural gas. A modernized algorithm of thermogasdynamic calculation of turbo-expanders in order to form the correct initial data for design calculations has been proposed. The objective of calculating turbo-expanders is to identify thermogasdynamic parameters and dimensions of the flow channel, rotational speed, and shaft power. Procedure of thermogasdynamic calculations is shown on the example of a turbo-expander running on natural gas. The result will simplify the process of selecting or designing turbo-expander units for gas distribution stations.