What is the Lowest Pressure on a Compound Gauge? lowest pressure that a compound gauge can measure is typically in the vacuum range, which extends down to -30 inHg or close to a full vacuum. These gauges are invaluable tools for monitoring both positive and negative pressures in a variety of applications, from HVAC systems to manufacturing and scientific research. Understanding the principles of compound gauges and their capabilities, including their lowest measurable pressure, is essential for their proper use and maintenance. https://www.ourmechanicalworld.com/archives/712