It really depends on what the application is. However, the best way to answer to this question is to show all of the various options so that an informed decision can be made. The Pressure Reference Chart below shows the different points of reference against which pressure is measured by the various pressure sensors.

Absolute pressure sensors reference pressure above absolute zero pressure, thus, absolute pressure sensors are capable of measuring pressure at any level.

Gage pressure sensors reference pressure above a sealed atmospheric pressure. The atmospheric pressure used is the atmospheric pressure that existed on the day the sensor was sealed.

Pressure Reference Chart

True gage pressure sensors reference pressure above the current atmospheric pressure. Because air can enter and exit through a vent in the sensor, the atmospheric pressure referenced is today’s atmospheric pressure.

Vacuum pressure sensors reference pressure of a vacuum below atmospheric pressure. Vacuum pressure sensors are scaled to report decreasing negative pressure as increasing positive voltage.