A digital manifold gauge having a gauge assembly with a display, one or more selectors, and a circuit board wherein the gauge assembly is rotatably disposed within a gauge housing and adapted to rotate to provide a plurality of viewing positions for the user. The circuit board is in electrical communication with a sensor port and the sensor port is adapted to receive a sensor transducer, such as a pressure transducer. The gauge includes internal software and logic for data processing and manipulation. The gauge includes a software algorithm adapted to convert pressure data transmitted to the circuit board from the pressure transducer into temperature data. The temperature and pressure data can be displayed on the display in real time and the gauge can also provide graphing and charting of the pressure-temperature relationship. The gauge is compatible with a variety of refrigerants and other fluids flowing through HVAC systems.