PSI Converter

Convert PSI (pounds per square inch) to other pressure units including Pascal, bar, atmosphere, kilopascal, and more.

Transform PSI values to various pressure units used in engineering, automotive, industrial, and scientific applications. Supports SI units, imperial units, and specialized pressure measurements.

Examples

Click on any example to load it into the calculator.

Standard Atmospheric Pressure

Atmospheric

Convert standard atmospheric pressure from PSI to other units commonly used in meteorology and aviation.

PSI Value: 14.696 PSI

Convert To: atm

Car Tire Pressure

Tire

Convert typical car tire pressure from PSI to bar, which is commonly used in European specifications.

PSI Value: 32 PSI

Convert To: bar

Hydraulic System Pressure

Hydraulic

Convert high-pressure hydraulic system pressure from PSI to megapascal for engineering applications.

PSI Value: 3000 PSI

Convert To: MPa

Medical Pressure

Medical

Convert medical pressure measurement from PSI to kilopascal for healthcare applications.

PSI Value: 2.9 PSI

Convert To: kPa

Other Titles
Understanding PSI Conversion: A Comprehensive Guide
Master the art of PSI (pounds per square inch) conversion to other pressure units. Learn about PSI applications, conversion factors, and real-world usage across different industries.

What is PSI and Why Convert It?

  • Definition and Origin of PSI
  • Global Usage and Regional Preferences
  • Importance of PSI Conversion
PSI (pounds per square inch) is a unit of pressure commonly used in the United States and some other countries. It represents the pressure exerted by one pound of force applied over one square inch of area. PSI is widely used in automotive, industrial, and engineering applications, but many countries and industries prefer other units like Pascal, bar, or atmosphere. This makes PSI conversion essential for international collaboration and cross-border projects.
The Fundamental Definition of PSI
PSI is defined as the pressure resulting from a force of one pound-force applied to an area of one square inch. Mathematically, 1 PSI = 1 lbf/in². This unit is part of the imperial system of measurements and is commonly used in the United States for various pressure applications. The conversion to SI units (Pascal) is based on the relationship: 1 PSI = 6894.757 Pa. This conversion factor is exact and provides the foundation for all PSI conversions.
Regional and Industry-Specific Usage Patterns
PSI usage varies significantly across regions and industries. The United States primarily uses PSI for automotive tire pressure, hydraulic systems, and industrial applications. Europe commonly uses bar for similar applications, while scientific research often prefers Pascal or kilopascal. Aviation uses inches of mercury (inHg) for atmospheric pressure in the US, while other countries use hectopascals. Understanding these regional preferences is crucial for effective communication and collaboration.
The Need for Accurate PSI Conversion
Accurate PSI conversion is essential for several reasons. International engineering projects require consistent pressure units across different countries. Scientific research often needs to compare data from different sources using various units. Automotive and industrial equipment specifications may need to be converted for international markets. Additionally, regulatory compliance often requires specific pressure units depending on the jurisdiction and application.

Common PSI Conversion Factors:

  • 1 PSI = 6894.757 Pascal (Pa)
  • 1 PSI = 6.894757 kilopascal (kPa)
  • 1 PSI = 0.0689476 bar
  • 1 PSI = 0.068046 atmosphere (atm)

Step-by-Step Guide to Using the PSI Converter

  • Input Validation and Preparation
  • Unit Selection Strategy
  • Result Interpretation and Verification
Using the PSI converter effectively requires understanding the input requirements, selecting appropriate target units, and interpreting results correctly. This systematic approach ensures accurate conversions and meaningful results for your specific application.
1. Preparing Your PSI Input
Start by identifying the PSI value you need to convert. Ensure the value is positive and represents the actual pressure measurement in PSI. For scientific or engineering applications, consider the precision of your original measurement—don't enter more significant figures than your measurement accuracy justifies. Common PSI values include tire pressure (30-35 PSI), atmospheric pressure (14.696 PSI), and hydraulic system pressure (1000-5000 PSI).
2. Selecting the Target Unit
Choose the target unit based on your application requirements. For international engineering projects, Pascal or kilopascal are often preferred. For European applications, bar is commonly used. For scientific research, Pascal or kilopascal align with SI standards. For automotive applications in different regions, you might need bar (Europe) or PSI (US). Consider your audience and the standards they follow when selecting the target unit.
3. Understanding Conversion Results
The converter provides the converted value with appropriate precision. For most applications, 3-4 significant figures are sufficient. The conversion factor shows the mathematical relationship between PSI and the target unit, which can be useful for understanding the scale difference. Always verify that the result makes sense—for example, 14.696 PSI should convert to approximately 1 atm or 101.325 kPa. If the result seems unreasonable, double-check your input value.
4. Practical Application Considerations
Consider the context of your PSI conversion. For automotive applications, ensure you're using the appropriate pressure reference (gauge vs. absolute pressure). For atmospheric pressure, remember that standard atmospheric pressure is 14.696 PSI. For industrial applications, verify whether your PSI measurement is absolute or gauge pressure, as this affects the conversion context. Always verify that your converted values are appropriate for your specific use case.

Common PSI Reference Points:

  • Standard Atmospheric Pressure: 14.696 PSI = 1 atm = 101.325 kPa
  • Automotive Tire Pressure: 32 PSI = 2.21 bar = 220.6 kPa
  • Hydraulic System: 3000 PSI = 206.8 bar = 20.68 MPa
  • Medical Applications: 2.9 PSI = 0.2 bar = 20 kPa

Real-World Applications and Industry Standards

  • Automotive and Transportation
  • Industrial and Manufacturing
  • Aerospace and Aviation
  • Medical and Healthcare
PSI conversion finds applications across diverse industries, each with specific requirements and standards. Understanding these applications helps in selecting appropriate target units and interpreting results correctly for different professional contexts.
Automotive and Transportation Applications
In the automotive industry, PSI is the standard unit for tire pressure in the United States, with typical values ranging from 30-35 PSI for passenger vehicles. European specifications often use bar, requiring conversion for international vehicles. Hydraulic brake systems operate at 1000-2000 PSI, while fuel injection systems may use 30-60 PSI. Air suspension systems typically operate at 50-150 PSI. These conversions are essential for vehicle maintenance, safety compliance, and international market requirements.
Industrial and Manufacturing Standards
Industrial applications use PSI extensively for hydraulic systems, pneumatic controls, and pressure vessels. Hydraulic systems typically operate in the 1000-5000 PSI range, requiring conversion to MPa for international engineering standards. Pneumatic systems often use 80-120 PSI, converting to bar for European equipment specifications. Pressure vessels and piping systems require precise pressure measurements and conversions for safety compliance and international code requirements.
Aerospace and Aviation Requirements
Aviation applications use various pressure units depending on the system and region. Cabin pressure is typically measured in PSI (US) or hectopascals (international), requiring conversion for international flights. Hydraulic systems in aircraft operate at 3000-5000 PSI, with specifications often provided in both PSI and MPa. Fuel system pressure may be specified in PSI or bar depending on the aircraft manufacturer and operating region.
Medical and Healthcare Applications
Medical applications use specialized pressure units, but PSI conversions are sometimes needed for equipment specifications and international standards. Ventilator settings may be specified in cmH₂O but converted to PSI for US equipment. Blood pressure is measured in mmHg but may need conversion to PSI for certain medical device specifications. Medical gas systems often use PSI for pressure specifications, requiring conversion to other units for international compliance.

Industry-Specific PSI Ranges:

  • Automotive Tires: 30-35 PSI (2.1-2.4 bar)
  • Hydraulic Systems: 1000-5000 PSI (69-345 bar)
  • Pneumatic Systems: 80-120 PSI (5.5-8.3 bar)
  • Aircraft Hydraulics: 3000-5000 PSI (207-345 bar)

Common Misconceptions and Conversion Pitfalls

  • Gauge vs. Absolute Pressure Confusion
  • Unit System Mixing Errors
  • Precision and Rounding Issues
  • Context-Dependent Conversions
PSI conversion errors often stem from misunderstandings about pressure types, unit systems, and measurement context. Recognizing these common pitfalls helps ensure accurate conversions and prevents costly mistakes in engineering and industrial applications.
Gauge vs. Absolute Pressure Confusion
One of the most common errors is confusing gauge pressure with absolute pressure when working with PSI. Gauge pressure is measured relative to atmospheric pressure, while absolute pressure is measured relative to a perfect vacuum. Gauge PSI = Absolute PSI - 14.696 PSI (atmospheric pressure). This difference is crucial in applications like tire pressure (gauge) vs. atmospheric pressure measurements (absolute). Always verify which type of pressure your PSI measurement represents and convert accordingly.
Unit System Mixing and Inconsistent References
Mixing PSI with other units from different systems without proper conversion can lead to significant errors. For example, using PSI values directly in calculations that expect Pascal can result in errors of several orders of magnitude. Similarly, using PSI (imperial) and bar (metric) in the same calculation without conversion can cause confusion. Always ensure consistency in unit systems throughout your calculations and clearly specify which units you're using.
Precision and Significant Figure Management
Maintaining appropriate precision throughout PSI conversions is essential. Converting a PSI measurement with 2 significant figures to a result with 6 significant figures gives a false impression of accuracy. The precision of your result should reflect the precision of your original PSI measurement. For example, if your pressure gauge reads 30 PSI (2 significant figures), the converted value in kPa should also have 2 significant figures (210 kPa, not 206.843 kPa).
Context-Dependent Conversion Requirements
Some PSI conversions depend on specific conditions or contexts. For example, the conversion between PSI and height in a fluid column depends on the fluid density and local gravity. Standard conversions assume standard conditions (1 atm, 20°C, standard gravity). For high-precision applications or non-standard conditions, additional corrections may be necessary. Always consider whether your application requires standard conversion factors or context-specific adjustments.

Common PSI Conversion Errors:

  • Confusing PSI (gauge) with PSI (absolute) in tire pressure applications
  • Using PSI and bar interchangeably without conversion in engineering calculations
  • Applying atmospheric pressure corrections incorrectly in vacuum applications
  • Mixing imperial and metric pressure units in the same calculation

Mathematical Derivation and Conversion Examples

  • Conversion Factor Derivation
  • Step-by-Step Calculation Methods
  • Verification and Cross-Checking
  • Advanced Conversion Techniques
Understanding the mathematical foundation of PSI conversions helps ensure accuracy and provides confidence in the results. The conversion factors are derived from fundamental physical relationships and can be verified through multiple methods.
Derivation of PSI Conversion Factors
The conversion factor from PSI to Pascal is derived from the fundamental definitions: 1 PSI = 1 lbf/in². Converting to SI units: 1 lbf = 4.448222 N and 1 in² = 0.00064516 m². Therefore, 1 PSI = (4.448222 N) / (0.00064516 m²) = 6894.757 N/m² = 6894.757 Pa. This exact conversion factor forms the basis for all PSI conversions. Other conversion factors are derived from this fundamental relationship and the definitions of other pressure units.
Step-by-Step Conversion Methodology
To convert PSI to any other unit, follow this systematic approach: 1) Convert PSI to Pascal using the exact conversion factor (1 PSI = 6894.757 Pa), 2) Convert from Pascal to the target unit using the appropriate conversion factor, 3) Apply appropriate rounding based on the precision of the original measurement. For example, to convert 30 PSI to bar: 30 PSI × 6894.757 Pa/PSI = 206,842.71 Pa, then 206,842.71 Pa ÷ 100,000 Pa/bar = 2.07 bar.
Verification and Cross-Checking Methods
Verify PSI conversions using multiple methods. Reverse conversion: convert the result back to PSI and compare with the original value. Reference points: use known conversion values like 14.696 PSI = 1 atm = 101.325 kPa. Unit relationships: verify that the conversion maintains proper relationships between units (e.g., 1 bar = 100 kPa). Dimensional analysis: ensure that the units cancel properly in the conversion process.
Advanced Conversion Techniques and Considerations
For high-precision applications, consider additional factors that may affect PSI conversions. Temperature effects: pressure measurements may need temperature corrections for very precise applications. Altitude effects: atmospheric pressure varies with altitude, affecting gauge pressure measurements. Local gravity: very precise measurements may need local gravity corrections. These factors are typically negligible for most applications but become important for high-precision scientific and engineering work.

Mathematical Conversion Examples:

  • 30 PSI to bar: 30 × 6894.757 ÷ 100000 = 2.07 bar
  • 100 PSI to kPa: 100 × 6894.757 ÷ 1000 = 689.5 kPa
  • 14.696 PSI to atm: 14.696 × 6894.757 ÷ 101325 = 1.000 atm
  • 1000 PSI to MPa: 1000 × 6894.757 ÷ 1000000 = 6.895 MPa