Psi Converter

Pounds per Square Inch, or PSI, is the standard unit of pressure in the imperial and U.S. customary systems. It's a measurement we encounter daily, from inflating car tires to checking water pressure. However, in a globalized world of science and engineering, converting PSI to metric units like kilopascals (kPa) and bar is a frequent necessity. This article provides everything you need to know about PSI conversion, complete with formulas, examples, and a user-friendly PSI converter.

What is PSI?

PSI (Pounds per Square Inch) measures the pressure resulting from a force of one pound-force applied to an area of one square inch. Its widespread use in the United States makes it a critical unit to understand and convert. For example, tire pressure is almost universally measured in PSI in the U.S.

It is crucial to distinguish between different types of PSI measurements, particularly PSIG and PSIA. Our PSIG to PSIA Converter explains this in detail, but in short:

• PSIG (Gauge PSI): Pressure relative to the surrounding atmospheric pressure.
• PSIA (Absolute PSI): Pressure relative to a perfect vacuum.

Most common applications, like tire pressure, use PSIG.

Core Conversion Formulas

All conversions to and from PSI are based on established mathematical relationships. Here are the most important ones:

PSI to Kilopascals (kPa)

The kilopascal is a standard metric unit. The conversion is:

1 PSI = 6.89476 kPa

To convert PSI to kPa, multiply your PSI value by 6.89476.

PSI to Bar

Bar is another common metric unit, roughly equivalent to atmospheric pressure.

1 PSI = 0.0689476 bar

To convert PSI to bar, multiply your PSI value by 0.0689476 (or divide by approximately 14.504).

PSI to Standard Atmospheres (atm)

Atmospheres are often used in scientific contexts.

1 PSI = 0.068046 atm

To convert PSI to atm, multiply your PSI value by 0.068046.

How to Use the PSI Converter

Our calculator simplifies these conversions into two easy steps:

1. Enter Your Value: You can input a value either in the "PSI" field or the "Converted Value" field.
2. Select the Unit: Use the dropdown menu to choose the unit you want to convert to or from (e.g., kPa, bar, atm).

The calculator works both ways. If you enter a PSI value, it shows the equivalent in the selected unit. If you enter a value in the other field, it converts it back to PSI.

Practical Example: Workshop Air Pressure

A pneumatic tool from Europe is rated for a maximum operating pressure of 6.2 bar. Your workshop's air compressor gauge reads in PSI. What is the maximum safe PSI setting?

• Action: In the converter, select "Bar" from the dropdown menu.
• Input: Enter "6.2" into the "Converted Value" field.
• Calculation: The tool computes 6.2 / 0.0689476.
• Output: The result is approximately 89.92 PSI. You know not to exceed this pressure for the tool.

PSI Conversion Chart

Here is a quick reference chart for common PSI values:

Frequently Asked Questions (FAQ)

Is PSI an imperial or metric unit?

PSI is an imperial and U.S. customary unit. The corresponding SI (metric) unit is the Pascal (Pa).

How much is atmospheric pressure in PSI?

Standard atmospheric pressure at sea level is approximately 14.7 PSI.

What is a common use for low-pressure measurements?

Low pressures, often measured in inches of water, are critical in HVAC systems for monitoring airflow and fan performance. You can use our PSI to Inches of Water Converter for this.

External Resources for Further Reading:

• NASA - What is Pressure? - An educational overview of pressure concepts.
• National Physical Laboratory (UK) - The Pascal - A detailed explanation of the SI unit for pressure.