Convert pressure between bar, PSI, Pascal (Pa), kilopascal (kPa), megapascal (MPa), and kilogram-force per square centimeter (kg/cm²) with this pressure conversion tool. Perfect for anyone needing quick pressure conversions – from marine engineers managing fuel system pressures to hydraulic technicians calibrating equipment, or vessel operators verifying gauge readings across different measurement systems.
Use of this calculator/converter is at own risk. Please conduct extra calculations or consult a specialist to verify results.
How to Use the Pressure Converter
- Enter your value in any of the input fields
- View instant conversions
- Delete or click “Clear” to do another conversion
The converter provides accurate results using standard pressure conversion formulas, ensuring precision for professional maritime operations, fuel system management, and hydraulic equipment specifications.
Common Pressure Conversions
Maritime Industry Reference Pressures
Bunker Fuel System Pressures:
- Atmospheric pressure after bunkering: 1.01325 bar = 14.7 PSI = 101,325 Pa = 101.325 kPa = 0.101325 MPa = 1.033 kg/cm²
- Fuel transfer pump discharge: 5-10 bar = 72.5-145 PSI = 500,000-1,000,000 Pa = 500-1,000 kPa
- Fuel injection pressure (diesel): 200-300 bar = 2,900-4,350 PSI = 20-30 MPa
- Fuel injection pressure (common rail): 1,000-2,500 bar = 14,500-36,250 PSI = 100-250 MPa
Hydraulic System Pressures:
- Steering gear systems: 70-150 bar = 1,015-2,175 PSI = 7-15 MPa
- Deck crane hydraulics: 200-350 bar = 2,900-5,075 PSI = 20-35 MPa
- Winch systems: 150-250 bar = 2,175-3,625 PSI = 15-25 MPa
- Hatch cover actuators: 100-200 bar = 1,450-2,900 PSI = 10-20 MPa
- Ballast pump discharge: 3-8 bar = 43.5-116 PSI = 300-800 kPa
Tank and Storage Pressures:
- Fuel tank venting pressure: 0.02-0.05 bar = 0.29-0.73 PSI = 2-5 kPa
- Inert gas system: 0.2-0.5 bar = 2.9-7.25 PSI = 20-50 kPa
- Cargo tank pressure (tankers): 0.1-0.3 bar = 1.45-4.35 PSI = 10-30 kPa
- Compressed air systems: 7-10 bar = 101.5-145 PSI = 0.7-1.0 MPa
Engine System Pressures:
- Lubricating oil pressure: 3-5 bar = 43.5-72.5 PSI = 300-500 kPa
- Cooling water pressure: 2-4 bar = 29-58 PSI = 200-400 kPa
- Starting air pressure: 25-30 bar = 362.5-435 PSI = 2.5-3.0 MPa
- Turbocharger boost pressure: 2-4 bar = 29-58 PSI = 200-400 kPa
General Reference Pressures
Standard Atmospheric Pressure:
- 1 atmosphere = 1.01325 bar = 14.7 PSI = 101,325 Pa = 101.325 kPa = 0.101325 MPa = 1.033 kg/cm²
Common Industrial Pressures:
- Low pressure: 1-10 bar = 14.5-145 PSI = 0.1-1.0 MPa
- Medium pressure: 10-100 bar = 145-1,450 PSI = 1-10 MPa
- High pressure: 100-1,000 bar = 1,450-14,500 PSI = 10-100 MPa
- Ultra-high pressure: 1,000+ bar = 14,500+ PSI = 100+ MPa
Pressure Conversion Formulas
Bar Conversions
Bar to PSI:
PSI = Bar × 14.5
Example: Convert 5 bar (typical fuel transfer pressure) to PSI
- PSI = 5 × 14.5
- PSI = 72.5 PSI
Bar to Pascal:
Pa = Bar × 100,000
Example: Convert 3 bar (lubricating oil pressure) to Pascal
- Pa = 3 × 100,000
- Pa = 300,000 Pa
Bar to kPa:
kPa = Bar × 100
Example: Convert 7 bar (compressed air) to kPa
- kPa = 7 × 100
- kPa = 700 kPa
Bar to MPa:
MPa = Bar × 0.1
Example: Convert 200 bar (hydraulic crane) to MPa
- MPa = 200 × 0.1
- MPa = 20 MPa
Bar to kg/cm²:
kg/cm² = Bar × 1.02
Example: Convert 10 bar to kg/cm²
- kg/cm² = 10 × 1.02
- kg/cm² = 10.2 kg/cm²
PSI Conversions
PSI to Bar:
Bar = PSI × 0.0689
Example: Convert 145 PSI to bar
- Bar = 145 × 0.0689
- Bar = 9.99 bar (approximately 10 bar)
PSI to Pascal:
Pa = PSI × 6,894.76
Example: Convert 50 PSI to Pascal
- Pa = 50 × 6,894.76
- Pa = 344,738 Pa
PSI to kPa:
kPa = PSI × 6.89476
Example: Convert 100 PSI to kPa
- kPa = 100 × 6.89476
- kPa = 689.476 kPa
PSI to MPa:
MPa = PSI × 0.00689
Example: Convert 2,900 PSI (hydraulic system) to MPa
- MPa = 2,900 × 0.00689
- MPa = 19.98 MPa (approximately 20 MPa)
PSI to kg/cm²:
kg/cm² = PSI × 0.0703
Example: Convert 145 PSI to kg/cm²
- kg/cm² = 145 × 0.0703
- kg/cm² = 10.19 kg/cm²
Pascal (Pa) Conversions
Pascal to Bar:
Bar = Pa ÷ 100,000
Example: Convert 500,000 Pa to bar
- Bar = 500,000 ÷ 100,000
- Bar = 5 bar
Pascal to PSI:
PSI = Pa × 0.000145
Example: Convert 300,000 Pa to PSI
- PSI = 300,000 × 0.000145
- PSI = 43.5 PSI
Pascal to kPa:
kPa = Pa ÷ 1,000
Example: Convert 101,325 Pa (atmospheric pressure) to kPa
- kPa = 101,325 ÷ 1,000
- kPa = 101.325 kPa
Pascal to MPa:
MPa = Pa ÷ 1,000,000
Example: Convert 20,000,000 Pa to MPa
- MPa = 20,000,000 ÷ 1,000,000
- MPa = 20 MPa
Pascal to kg/cm²:
kg/cm² = Pa × 0.0000102
Example: Convert 500,000 Pa to kg/cm²
- kg/cm² = 500,000 × 0.0000102
- kg/cm² = 5.1 kg/cm²
Kilopascal (kPa) Conversions
kPa to Bar:
Bar = kPa × 0.01
Example: Convert 500 kPa to bar
- Bar = 500 × 0.01
- Bar = 5 bar
kPa to PSI:
PSI = kPa × 0.145
Example: Convert 700 kPa to PSI
- PSI = 700 × 0.145
- PSI = 101.5 PSI
kPa to Pascal:
Pa = kPa × 1,000
Example: Convert 300 kPa to Pascal
- Pa = 300 × 1,000
- Pa = 300,000 Pa
kPa to MPa:
MPa = kPa ÷ 1,000
Example: Convert 15,000 kPa to MPa
- MPa = 15,000 ÷ 1,000
- MPa = 15 MPa
kPa to kg/cm²:
kg/cm² = kPa × 0.0102
Example: Convert 500 kPa to kg/cm²
- kg/cm² = 500 × 0.0102
- kg/cm² = 5.1 kg/cm²
Megapascal (MPa) Conversions
MPa to Bar:
Bar = MPa × 10
Example: Convert 2.5 MPa (starting air pressure) to bar
- Bar = 2.5 × 10
- Bar = 25 bar
MPa to PSI:
PSI = MPa × 145
Example: Convert 20 MPa (hydraulic crane) to PSI
- PSI = 20 × 145
- PSI = 2,900 PSI
MPa to Pascal:
Pa = MPa × 1,000,000
Example: Convert 0.5 MPa to Pascal
- Pa = 0.5 × 1,000,000
- Pa = 500,000 Pa
MPa to kPa:
kPa = MPa × 1,000
Example: Convert 3 MPa to kPa
- kPa = 3 × 1,000
- kPa = 3,000 kPa
MPa to kg/cm²:
kg/cm² = MPa × 10.2
Example: Convert 5 MPa to kg/cm²
- kg/cm² = 5 × 10.2
- kg/cm² = 51 kg/cm²
Kilogram-force per Square Centimeter (kg/cm²) Conversions
kg/cm² to Bar:
Bar = kg/cm² ÷ 1.02
Example: Convert 10.2 kg/cm² to bar
- Bar = 10.2 ÷ 1.02
- Bar = 10 bar
kg/cm² to PSI:
PSI = kg/cm² × 14.223
Example: Convert 5 kg/cm² to PSI
- PSI = 5 × 14.223
- PSI = 71.115 PSI
kg/cm² to Pascal:
Pa = kg/cm² × 98,066.5
Example: Convert 3 kg/cm² to Pascal
- Pa = 3 × 98,066.5
- Pa = 294,199.5 Pa
kg/cm² to kPa:
kPa = kg/cm² × 98.0665
Example: Convert 7 kg/cm² to kPa
- kPa = 7 × 98.0665
- kPa = 686.47 kPa
kg/cm² to MPa:
MPa = kg/cm² × 0.09807
Example: Convert 100 kg/cm² to MPa
- MPa = 100 × 0.09807
- MPa = 9.807 MPa
Understanding Pressure Units and Scales
Bar
The bar is a metric pressure unit widely used in European maritime operations, hydraulic systems, and fuel specifications. One bar is defined as exactly 100,000 pascals, making it convenient for practical engineering applications. The bar is slightly less than atmospheric pressure (1 bar ≈ 0.987 atmospheres), but close enough that it’s often used interchangeably in casual reference.
In maritime applications, bar is the standard unit for hydraulic system specifications, fuel pump ratings, and pressure gauge calibration across European-built vessels and equipment. Most modern pressure gauges display bar as the primary unit, with PSI as a secondary reference.
Pounds per Square Inch (PSI)
PSI is the imperial pressure unit commonly used in American maritime equipment, specifications, and documentation. One PSI represents the pressure exerted by one pound-force applied to one square inch of area. While less common in international maritime standards, PSI remains prevalent in U.S.-manufactured equipment, particularly hydraulic systems, fuel pumps, and pressure relief valves.
Understanding PSI conversions is essential when working with mixed equipment specifications or coordinating operations involving both metric and imperial measurement systems. Many pressure gauges display both bar and PSI for universal compatibility.
Pascal (Pa), Kilopascal (kPa), and Megapascal (MPa)
The pascal is the SI (International System of Units) base unit for pressure, defined as one newton per square meter. Because the pascal is a relatively small unit, maritime applications typically use kilopascals (kPa = 1,000 Pa) for low-pressure systems and megapascals (MPa = 1,000,000 Pa) for high-pressure applications.
Practical Maritime Applications:
- Pascal (Pa): Rarely used directly; primarily for scientific calculations
- Kilopascal (kPa): Tank venting pressures, low-pressure fuel systems, ventilation systems
- Megapascal (MPa): High-pressure fuel injection, hydraulic systems, compressed gas storage
The pascal system provides precise scientific measurement and is increasingly common in international maritime regulations and technical specifications.
Kilogram-force per Square Centimeter (kg/cm²)
The kg/cm² unit, also written as kgf/cm², represents the pressure exerted by one kilogram-force on one square centimeter. While not an SI unit, kg/cm² remains common in older equipment specifications, particularly from Asian and European manufacturers, and appears frequently on legacy pressure gauges and technical documentation.
One kg/cm² is approximately equal to one atmosphere and very close to one bar (1 kg/cm² = 0.9807 bar), making rough conversions straightforward. However, for precise engineering calculations, use exact conversion factors to avoid cumulative errors in system design and safety calculations.
Why Multiple Pressure Units Exist in Maritime Operations
Maritime vessels operate globally and incorporate equipment from manufacturers worldwide, each using their regional measurement standards. A single vessel might have:
- European hydraulic systems rated in bar
- American fuel pumps specified in PSI
- Japanese instrumentation displaying kg/cm²
- International regulations referencing kPa or MPa
This diversity requires marine engineers and operators to work fluently across multiple pressure measurement systems, making accurate conversion essential for safe operations, equipment specification, and regulatory compliance.
Gauge Pressure vs. Absolute Pressure
Maritime pressure measurements typically reference gauge pressure (pressure relative to atmospheric pressure) rather than absolute pressure (pressure relative to perfect vacuum). Gauge pressure readings show zero at atmospheric pressure, while absolute pressure shows approximately 1 bar (14.7 PSI) at sea level.
Critical Distinction:
- Gauge pressure: Used for most operational measurements (fuel systems, hydraulics, compressed air)
- Absolute pressure: Required for thermodynamic calculations, vacuum systems, and precise scientific measurements
Always verify whether specifications reference gauge or absolute pressure to avoid dangerous misinterpretation of system requirements.
Frequently Asked Questions
Why do maritime pressure gauges show multiple units?
Maritime pressure gauges typically display multiple units (bar, PSI, and sometimes kg/cm²) because vessels operate globally with equipment from different manufacturers using regional measurement standards. A vessel might have European hydraulic systems rated in bar, American fuel pumps specified in PSI, and Japanese instrumentation displaying kg/cm². Multiple-unit gauges eliminate conversion errors and allow operators to read pressures directly in the unit matching their equipment specifications or operational procedures.
What pressure should be verified after bunkering operations?
After completing bunkering operations, the pressure in the pipeline between the bunker manifold and flowmeter must read atmospheric pressure (approximately 1.01 bar or 14.7 PSI). This verification is a critical part of the bunker ticket validation process. If the pipeline pressure isn’t atmospheric, the line should be vented to avoid pressure buildup that could affect fuel quantity measurements or create safety hazards. The pressure gauge near the flowmeter provides this essential verification.
What are typical hydraulic system pressures on vessels?
Hydraulic system pressures vary by application. Steering gear systems typically operate at 70-150 bar (1,015-2,175 PSI), deck cranes at 200-350 bar (2,900-5,075 PSI), winch systems at 150-250 bar (2,175-3,625 PSI), and hatch cover actuators at 100-200 bar (1,450-2,900 PSI). Ballast pump discharge pressures are lower, typically 3-8 bar (43.5-116 PSI). Always verify specific equipment specifications, as actual operating pressures depend on manufacturer design, system configuration, and operational requirements.
How do I convert between bar and PSI quickly?
For quick conversions, multiply bar by 14.5 to get PSI, or multiply PSI by 0.0689 to get bar. For example, 5 bar × 14.5 = 72.5 PSI. For reverse conversion, 100 PSI × 0.0689 = 6.89 bar. These conversion factors provide accuracy sufficient for most operational purposes. For precise engineering calculations or safety-critical applications, use the exact conversion factors: 1 bar = 14.5038 PSI and 1 PSI = 0.0689476 bar.
What’s the difference between kPa and MPa?
Kilopascal (kPa) and megapascal (MPa) are both SI pressure units differing by a factor of 1,000. One MPa equals 1,000 kPa. Maritime applications use kPa for lower pressures like fuel tank venting (2-5 kPa) and ventilation systems, while MPa is used for high-pressure systems like fuel injection (100-250 MPa) and hydraulic equipment (10-35 MPa). To convert kPa to MPa, divide by 1,000. To convert MPa to kPa, multiply by 1,000.
Why is atmospheric pressure important in fuel system operations?
Atmospheric pressure verification is critical in fuel system operations because it confirms proper venting and accurate fuel quantity measurement. After bunkering, pipelines must be at atmospheric pressure (approximately 1.01 bar or 14.7 PSI) to ensure flowmeter readings accurately reflect delivered fuel quantities. Residual pressure in fuel lines can cause measurement errors, leading to disputes over delivered quantities or incorrect billing. Proper pressure management also prevents tank overpressure during fuel transfer operations.
What pressure units do international maritime regulations use?
International maritime regulations increasingly reference SI units (Pascal, kPa, MPa) as the standard, though bar remains widely accepted in European contexts. MARPOL, SOLAS, and IMO regulations typically specify pressures in kPa or MPa for consistency with international scientific standards. However, equipment specifications may still use bar or PSI depending on manufacturer origin. Marine professionals must be fluent in converting between all common pressure units to ensure regulatory compliance and safe equipment operation across different measurement systems.
How accurate do pressure measurements need to be for fuel systems?
Pressure measurements for fuel systems should be accurate to within ±2% of the reading for operational safety and regulatory compliance. Fuel injection systems require particularly precise pressure control, as variations affect combustion efficiency, emissions, and engine performance. Fuel transfer operations need accurate pressure monitoring to prevent tank overpressure and ensure safe venting. Always use calibrated pressure gauges and verify readings against multiple instruments when conducting critical operations like bunkering or fuel system commissioning.
What’s the relationship between kg/cm² and bar?
Kilogram-force per square centimeter (kg/cm²) and bar are very close in value, with 1 kg/cm² = 0.9807 bar, or conversely, 1 bar = 1.02 kg/cm². This near-equivalence means rough conversions can treat them as approximately equal (1 kg/cm² ≈ 1 bar), though precise engineering calculations should use exact conversion factors. The kg/cm² unit appears frequently on older equipment and Asian-manufactured instrumentation, while bar is the modern metric standard for European equipment and international specifications.
Gulf-Bunkering provides marine fuel trading solutions worldwide, connecting vessel operators with compliant fuel products through our knowledge of global supply networks, regional logistics, and port coordination. Accurate pressure measurement and conversion support safe fuel handling operations and equipment specification across international maritime operations. For marine fuel trading services, contact us at contact@gulf-bunkering.com