Gas meters are devices that measure gas flow, they can be of different designs, all are mechanical, but we distinguish them by the way gas flow is measured. The simplest is a bellows-to-ultrasonic gas meter. Given that I am employed at Brod-Gas Ltd, in this paper I will try to describe as much as possible the specific details and situations from practice and of course relate them to the theory. As the measurement technique advances all the time, there are also novelties and additional devices in the gas technology that give us more accurate consumption dana caused by the actual flow of gas, or since the locations of gas meters are different - they may be affected by external parameters (weather conditions). In addition to the flow rate and measuring the amount of gas, the safety of the gas meter is also important, and the gas meters need to be serviced, but of course users also need to be informed what the gas meter is.