What is PSI?

February 28, 2025
what is psi

At Mid-West Instrument, we specialize in providing accurate pressure measurement solutions for various industrial applications. One of the most commonly used units for measuring pressure is PSI, which stands for pounds per square inch. It’s used in pressure measurement across multiple industries, including oil & gas, HVAC, water treatment, and industrial processing. Understanding this unit and how it relates to different pressure measurement systems helps ensure that the correct instruments are used for specific applications.

Definition

PSI (pounds per square inch) is a unit of pressure that represents the force exerted over a one-square-inch area. It measures how much force is applied to a given surface area and is widely used in industrial, scientific, and commercial applications.

For example:

  • 1 PSI means that one pound of force is applied to an area of one square inch.
  • If a system is rated at 100 PSI, it means that 100 pounds of force is being exerted per square inch of surface.

PSI is used to measure gauge pressure, absolute pressure, and differential pressure, depending on the application. At Mid-West Instrument, our differential pressure gauges provide highly accurate readings to monitor pressure differences in industrial systems.

Converting to Other Units

In some industries, pressure is measured in other units. Understanding conversions ensures compatibility with international standards. Here are some common conversions:

  • 1 PSI = 6.895 kPa (kilopascals)
  • 1 PSI = 0.06895 bar
  • 1 PSI = 2.31 feet of water (ft H2O)
  • 1 PSI = 0.068046 atmospheres (atm)

For applications requiring different pressure units, Mid-West Instrument provides custom dial scales with multiple unit options, ensuring accurate pressure readings for any industry.

Conclusion

PSI (pounds per square inch) is a widely used unit of pressure measurement in industrial, automotive, oil & gas, and HVAC applications. Whether measuring gauge pressure (PSIG), absolute pressure (PSIA), or differential pressure (PSID), accurate readings are critical for system performance and safety. At Mid-West Instrument, we manufacture high-quality differential pressure gauges designed to provide precise measurements for a variety of industrial needs. Contact us today to find the right pressure gauge for your application.