Pressure Converter
Convert between PSI, bar, pascal, atmosphere, and other pressure units instantly.
How to Use the Pressure Converter
- Enter Value: Type the pressure value you want to convert in the input field
- Select Source Unit: Choose your starting unit from the dropdown (PSI, bar, pascal, etc.)
- Choose Target Unit: Pick the unit you want to convert to
- View Result: The converted value appears instantly in the result field
- Switch Units: Click the swap button to quickly reverse the conversion direction
Pressure Units Explained
PSI (Pounds per Square Inch)
PSI measures pressure as the force in pounds applied over one square inch of area. This unit is standard in the United States for tire pressure, hydraulic systems, and industrial equipment. Most car tires operate between 30-35 PSI, while truck tires may require 50-80 PSI.
Bar
Bar is a metric unit roughly equal to atmospheric pressure at sea level (1 bar ≈ 14.5 PSI). It's common in Europe for tire pressure ratings and weather forecasting. Many pressure gauges show both bar and PSI for convenience.
Pascal (Pa)
The Pascal is the SI unit for pressure, defined as one newton per square meter. Since it's a small unit, you'll often see kilopascals (kPa) or megapascals (MPa) in practice. Building codes and engineering specifications typically use kPa or MPa.
Atmosphere (atm)
One atmosphere equals the air pressure at sea level under standard conditions (101,325 Pa or 14.7 PSI). This unit is common in chemistry, diving, and scientific applications when discussing gas pressures and reactions.
Torr and mmHg
These units measure pressure based on mercury column height. Torr and mmHg are nearly identical (1 Torr = 1 mmHg). Medical professionals use mmHg for blood pressure readings, while Torr appears in vacuum system specifications.
Common Pressure Conversions
Quick Reference
Real-World Examples
Practical Applications
Automotive and Transportation
- Checking and adjusting tire pressure for fuel efficiency and safety
- Hydraulic brake systems in vehicles use pressure measurements
- Engine turbocharger boost pressure monitoring
- Shock absorber and suspension system specifications
Industrial and Engineering
- Pneumatic tools and air compressor settings
- HVAC system pressure testing and maintenance
- Gas cylinder storage and handling requirements
- Pressure vessel design and safety regulations
Safety Note: Always follow manufacturer specifications for pressure settings. Over-pressurization can cause equipment failure, injuries, or property damage. Under-pressurization may lead to poor performance or safety issues.
Frequently Asked Questions
When should I use PSI vs bar?
Use PSI when working with American equipment, tire pressure gauges, or following US specifications. Use bar for European equipment, international standards, or when working with metric systems. Many modern gauges show both units.
What's the difference between absolute and gauge pressure?
Gauge pressure measures relative to atmospheric pressure (what most pressure gauges show). Absolute pressure includes atmospheric pressure in the measurement. For example, 30 PSI gauge equals about 44.7 PSI absolute (30 + 14.7 atm).
How accurate do I need to be with pressure measurements?
Accuracy requirements depend on the application. Tire pressure can be within 1-2 PSI for most vehicles. Industrial systems may require precision within 0.1 PSI or better. Critical applications like medical equipment demand even tighter tolerances.
Why do tire pressure recommendations differ between PSI and bar?
The same tire pressure is simply expressed in different units. A tire rated at 2.2 bar equals 32 PSI. Check your vehicle's door jamb sticker or owner's manual for the correct pressure in your preferred unit.
Can I convert vacuum pressure using this tool?
Yes, but note that vacuum is typically measured as pressure below atmospheric. For example, 10 PSI vacuum means 10 PSI below atmospheric pressure. Some industries use negative values, while others use absolute pressure measurements.