kPa to PSI Converter

Relationship Between kPa and PSI

The conversion between kilopascals (kPa) and pounds per square inch (PSI) is a common pressure unit conversion between metric and imperial systems.

1 PSI = 6.89476 kPa

Therefore,

1 kPa = 0.145038 PSI

To convert kPa to PSI, we multiply the kPa value by 0.145038.

For example, 100 kPa equals 14.5038 PSI, which is close to standard atmospheric pressure (14.7 PSI at sea level).

Quick Reference:
Atmospheric pressure at sea level is approximately 101.325 kPa or 14.696 PSI. This conversion is essential for automotive tire pressure, hydraulic systems, compressed air applications, and many engineering calculations where both metric and imperial units are used.

Kilopascal (kPa)

What is a Kilopascal?

The kilopascal (symbol: kPa) is a unit of pressure in the International System of Units (SI). It equals 1,000 pascals, where one pascal is defined as one newton per square meter (N/m²). The kilopascal is the most practical SI unit for everyday pressure measurements, as the basic unit (pascal) is too small for most common applications.

History and Definition

The pascal is named after Blaise Pascal, the French mathematician and physicist who made significant contributions to the study of fluids and pressure. The kilopascal became widely adopted in countries using the metric system as it provides convenient values for common pressure ranges. 1 kPa = 1,000 Pa = 1,000 N/m².

Common Uses

• Atmospheric pressure: Standard atmospheric pressure is 101.325 kPa
• Automotive tire pressure: Typically 200-250 kPa (30-36 PSI)
• Weather forecasting: Often measured in hectopascals (hPa = 100 Pa = 0.1 kPa)
• Engineering specifications: Pressure ratings for pipes, valves, and vessels
• Compressed air systems: Industrial air compressors typically operate at 700-900 kPa
• Vacuum measurements: Low-pressure applications (0.1-100 kPa)
• Blood pressure monitors: Some digital devices display in kPa (normal ~16 kPa systolic)
• Respiratory equipment: Medical oxygen and ventilator pressures
• Hydraulic systems: Construction and industrial equipment
• Packaging standards: Vacuum-sealed food packaging specifications

Advantages of kPa

The kilopascal is part of the coherent SI system, making calculations straightforward. It provides convenient numerical values for most practical applications - not too large like pascals alone, but manageable for everyday use. Countries using the metric system prefer kPa for its scientific accuracy and international standardization.

Pounds per Square Inch (PSI)

What is PSI?

PSI (pounds per square inch) is a unit of pressure in the imperial system, widely used in the United States and some other countries. It represents the force in pounds applied to an area of one square inch. PSI is the standard pressure unit for many industrial, automotive, and consumer applications in countries using imperial measurements.

Historical Background

PSI developed alongside the imperial measurement system and became the standard pressure unit in English-speaking countries, particularly the United States. While many countries have transitioned to metric units, PSI remains prevalent in American engineering, manufacturing, and everyday applications. The unit is deeply embedded in standards, equipment, and practices across numerous industries.

Common Applications

• Tire Pressure: Car tires typically require 30-35 PSI, truck tires 50-80 PSI
• Hydraulic Systems: Construction equipment operates at 2,000-5,000 PSI
• Air Compressors: Workshop compressors typically run at 90-150 PSI
• Water Pressure: Residential water pressure is usually 40-80 PSI
• Pressure Washers: Consumer models: 1,500-3,000 PSI; Commercial: 3,000-8,000 PSI
• Scuba Tanks: Filled to 3,000-4,500 PSI
• Natural Gas Lines: Residential: 0.25 PSI; Commercial: 5-60 PSI
• Steam Boilers: Low pressure: 15 PSI; High pressure: 150+ PSI
• HVAC Systems: Refrigerant pressures typically 50-400 PSI
• Fire Sprinkler Systems: Typically 7-30 PSI

PSI in Industry

PSI is the dominant pressure unit in American manufacturing, construction, and automotive industries. Most pressure gauges, specifications, and equipment in the United States are calibrated in PSI. Understanding PSI to kPa conversion is essential for international trade, importing equipment, and working with global standards.

PSIA vs PSIG

There are two common PSI measurements: PSIA (pounds per square inch absolute) measures pressure relative to a perfect vacuum, while PSIG (pounds per square inch gauge) measures pressure relative to atmospheric pressure. For example, a tire gauge reading 32 PSIG means the pressure is 32 PSI above atmospheric pressure, or about 46.7 PSIA (32 + 14.7).

kPa to PSI Conversion Table

Common kPa to PSI conversions for reference: