Abstract: The present application discloses a metering system for calculating a real-time profit or loss of a gas station, including a metering module, a level gauge of the oil tank, and a communication management machine with a built-in data processing module; the metering module and the level gauge are respectively communicated with the communication management machine; the oil tank, an oil pipeline of the oil tank and an oil inlet of the fuel dispenser are respectively provided with a sensor array module for collecting density data of the oil therein; the sensor array module includes a plurality of oil density sensors; the sensor array modules are communicated with the communication management machine; the built-in data processing module receives and processes data from the metering module, the level gauge and the sensor array modules respectively.