Recently, the development of communication technologies, including the Internet of Things technology, has allowed to significantly automate and make people's lives easier. Internet of Things technologies are being implemented in various applications from agriculture to industrial sectors, from smart homes to smart cities. Due to this popularity, the number of smart devices is growing rapidly. Multiple forecasts already represent numbers of up to several billion devices in the next 5 years. Thus, the task of providing energy consumption for so many devices has become a priority in the development of Internet of Things. In order to study energy consumption, the simplest Internet thing based on RFID technology was tested, which allowed to calculate the service life of the battery located in the case of the radio frequency identification tag. Research subject. This article is about testing the power consumption of a typical Internet of Things device — RFID tags. Method. The studies are based on experimental methods, as well as statistical processing of measurement results. A laboratory bench for full-scale tests was developed with the support of the Rode and Schwartz Company, a testing procedure was developed, and an analysis was made of the energy consumption of the label under various operating conditions. Core results. The results of testing the battery life are presented. Practical relevance. The results of testing the RFID tag are presented, the battery life for the RFID tag is calculated. Practical significance. The results can be used when testing RFID tags and determining the operating time from various batteries. The presented laboratory bench scheme and testing technique can be used not only for RFID tags, but also for other types of Internet of Things devices.