Pressure measurements are critical across countless industries and applications - from inflating car tires to designing hydraulic systems, from calibrating HVAC equipment to monitoring industrial processes. Engineers, mechanics, technicians, and DIY enthusiasts all need to convert between pressure units regularly. Whether you're checking tire pressure in Europe using a gauge marked in bar while your car specifies PSI, or working on hydraulic equipment with specifications in different units, accurate pressure conversion is essential for safety and performance. Our free pressure converter handles all common pressure units with professional-grade precision, giving you instant conversions you can trust.
Pressure is defined as force applied perpendicular to a surface per unit area. In physics and engineering, it's measured in force per area units. Different fields and regions developed different units based on convenient reference points. PSI (Pounds per Square Inch) - Force of one pound distributed over one square inch. Common in US automotive, hydraulics, and pneumatics. Bar - Exactly 100,000 Pascals. Approximately equal to average atmospheric pressure. Widely used in Europe and industrial applications. Pascal (Pa) - SI unit: one Newton per square meter. Kilopascal (kPa) = 1,000 Pa. Megapascal (MPa) = 1,000,000 Pa. Atmosphere (atm) - Average sea level atmospheric pressure. 1 atm = 101,325 Pa. Used in chemistry and physics. Torr/mmHg - Millimeters of mercury. Medical blood pressure (120/80 mmHg), vacuum measurements. Inches of Mercury (inHg) - Common for vacuum and HVAC in the US. Food canning, automotive vacuum. Different units evolved because various applications found certain reference points more intuitive. Our converter bridges these systems.
Multi-Unit Conversion — Convert between PSI, bar, atm, kPa, Pa, MPa, Torr/mmHg, and inHg with a single tool. Instant Calculation — Results update automatically as you type; no waiting or clicking required. Precision Display — Shows multiple decimal places for engineering and scientific precision. Tire-Specific Focus — Special attention to common automotive pressure ranges and conversions. Mobile Optimized — Use on your smartphone at the garage, workshop, or job site. Free to Use — No registration, subscription, or hidden fees. Bookmark Friendly — Save for instant access whenever you need pressure conversions. Copy Results — One-click copying of converted values for documentation or sharing. Professional Grade — Accurate enough for industrial, automotive, and scientific applications. Works Offline — Page loads completely; internet only needed for initial access.
Using our pressure converter is straightforward: First, enter your pressure value in the input field. You can type any numeric value - whole numbers like 32, decimals like 35.5, or larger values like 150.8. Second, select your current unit from the first dropdown. Choose from PSI (common in US), bar (common in Europe), atm (atmospheres), kPa (kilopascals), Pa (Pascals), MPa (megapascals), Torr/mmHg (medical/vacuum), or inHg (inches of mercury). Third, select your target unit from the second dropdown. The converter handles all combinations - you can convert from any supported unit to any other. Fourth, view your result instantly. The converted value appears with appropriate precision. For engineering use, multiple decimal places are shown. Fifth, use the result for your application. Copy the value using the copy button if needed. The conversion relationship is shown so you understand how the calculation was performed.
Automotive and Tire Shops — Converting European vehicle tire specifications from bar to PSI for US customers. Checking imported vehicle tire pressures. Converting compressor ratings between units for proper equipment matching. HVAC and Refrigeration — Converting refrigerant pressures between PSI and bar for different equipment manuals. Understanding vacuum readings in HVAC systems. Calculating pressure differentials for air flow. Industrial and Manufacturing — Converting hydraulic system specifications for equipment from different countries. Checking pneumatic system pressures. Verifying compressed air system ratings. Plumbing and Piping — Converting water pressure specifications from municipal standards to equipment requirements. Understanding pressure ratings on fittings and valves from different manufacturers. Aviation and Aerospace — Converting cabin pressure specifications between units. Understanding pressure differentials in aircraft systems. Medical and Laboratory — Converting blood pressure readings between mmHg and other units. Understanding gas cylinder pressures. Converting vacuum chamber specifications.
Universal Compatibility — Works with all common pressure units used across industries and countries. No need to memorize conversion factors or use multiple tools. Instant and Accurate — Get precise conversions instantly without manual calculations. Eliminate human error from pressure unit conversions. Free and Available — No cost or registration requirements. Use it anytime, anywhere, on any device. Professional Reliability — Trusted by mechanics, engineers, and technicians who need accurate pressure conversions. Mobile Friendly — Works perfectly on smartphones for use in garages, workshops, and industrial sites. Educational Value — Learn about different pressure units and their relationships. Understand when to use each unit. Reference Tool — Bookmark for instant access whenever you encounter pressure measurements in unfamiliar units.
Automotive Technicians — Mechanics and tire shop workers dealing with vehicles from different markets. Converting pressure specifications from international vehicles. Checking tire pressures with gauges marked in different units. Mechanical Engineers — Engineers designing hydraulic, pneumatic, and fluid systems. Converting specifications from international suppliers. Calculating pressure drops and system requirements. HVAC Technicians — Refrigeration and air conditioning technicians working with system pressures. Converting between units on different equipment. Understanding vacuum pressures in HVAC systems. Industrial Maintenance Workers — Plant maintenance personnel checking equipment pressures. Converting between units on imported machinery. Verifying compressed air system pressures. Plumbers and Pipefitters — Professionals working with water, steam, and gas systems. Converting municipal pressure specifications to equipment ratings. Understanding pressure ratings on components from different countries. Pilots and Aviation Personnel — Checking cabin pressure and aircraft system pressures. Converting between units in different aircraft manuals. Scuba Divers — Understanding tank pressures and depth pressure calculations. Converting between bar, PSI, and atm for different diving environments. DIY Enthusiasts — Home mechanics and hobbyists working on projects. Converting pressure specifications in online guides. Understanding pressure requirements for tools and equipment.
Getting started with our pressure converter takes just seconds: Open the converter in any web browser on your device. The tool works on computers, tablets, and smartphones. The page loads completely so it works even with spotty internet. Enter your pressure value in the input field. Type any number - whole numbers like 32, 150, or 3000, or decimals like 35.5, 100.7 for precise values. Select your current unit from the first dropdown. Choose from PSI, bar, atm, kPa, Pa, MPa, Torr/mmHg, or inHg. Each unit is clearly labeled with its common usage context. Select your target unit from the second dropdown. The converter handles all combinations - PSI to bar, kPa to PSI, atm to bar, and any other conversion you need. View your converted result instantly. The value updates automatically showing the conversion with appropriate precision. Multiple decimal places are shown for engineering accuracy. Copy the result if needed using the copy button. Use the converted value for your application. The conversion formula is also shown so you understand the relationship between units.
Know Your Units — Understand which unit you're converting FROM and which you're converting TO. PSI and bar are the most common automotive units, while atm and mmHg are used in scientific contexts. Check Your Gauge — Verify what units your pressure gauge displays before converting. Some gauges show multiple units, others require conversion. Maintain Pressure Ranges — Stay within recommended pressure ranges for your application. Never exceed maximum rated pressures for tires, hoses, or equipment. Account for Temperature — Pressure changes with temperature (Gay-Lussac's law). Tire pressures increase when hot, decrease when cold. Always check tire pressure when tires are cold for accurate readings. Use Proper Tools — Always use pressure gauges rated for your application. Tire gauges, HVAC gauges, and industrial pressure gauges serve different purposes. Understand Gauge vs Absolute — Most everyday measurements are gauge pressure (above atmospheric). Applications like scuba diving and vacuum systems often use absolute pressure. PSI is commonly used for this distinction. Safety First — High-pressure systems can be dangerous. Always use proper safety equipment when working with pressurized systems. Never exceed rated pressures. Steam systems are particularly dangerous - pressure vessels require certification. Keep Reference Values — Memorize common conversions: 1 bar ≈ 14.5 PSI, 1 atm ≈ 14.7 PSI, atmospheric pressure ≈ 15 PSI/1 bar/100 kPa. These references help verify your conversions are reasonable.
Pressure Scope — Our converter handles common pressure ranges from near-vacuum to very high pressures (up to several thousand bar/PSI). Extremely high pressures (hydraulic forming, diamond synthesis) may be outside practical ranges. Unit Coverage — While we cover all major pressure units (PSI, bar, atm, kPa, Pa, MPa, Torr/mmHg, inHg), some specialized units like kgf/cm², N/m² variants, or non-standard units are not included. Temperature Effects — The converter handles pressure unit conversions only. It does not account for temperature effects on pressure, which can be significant in sealed systems. Maintains Constant Temperature — For precise work, remember that pressure changes with temperature. Our converter assumes conversions at the same temperature. Gauge vs Absolute — The converter does not automatically distinguish between gauge and absolute pressure. You must understand which type of pressure you're working with. User must provide correct unit identification. Scientific Notation — While the converter handles very large and small numbers, scientific notation entry (like 1.5e5) is not supported. Enter values as standard numbers. Pressure Values Only — This tool is for pressure conversions only. It does not convert volume, flow rate, or force measurements. No Safety Advice — The converter does not provide safety recommendations for pressurized systems. Always follow proper safety procedures and use equipment rated for your actual pressures.
To convert PSI (pounds per square inch) to bar, divide the PSI value by 14.504. Alternatively, multiply by 0.06895. The formula is: bar = PSI ÷ 14.504. Common conversions: 30 PSI = 2.07 bar (typical car tire), 50 PSI = 3.45 bar (heavy vehicle tire), 100 PSI = 6.89 bar (hydraulic system), 14.5 PSI = 1 bar (atmospheric pressure equivalent). Quick approximations: 15 PSI ≈ 1 bar, 30 PSI ≈ 2 bar, 45 PSI ≈ 3 bar. For precise work, always use the exact conversion factor: 1 bar = 14.5038 PSI. Our converter provides exact conversions automatically. Simply enter your PSI value and select bar as the target unit. The result updates instantly, showing the precise conversion with multiple decimal places.
PSI, bar, and kPa are different units for measuring pressure: PSI (Pounds per Square Inch) - Imperial/US customary unit. Measures force in pounds applied over one square inch. Common in the US for tire pressure, hydraulics, and compressed air systems. 1 PSI = force of 1 pound over 1 square inch. Bar - Metric unit widely used worldwide. Defined as 100,000 Pascals (100 kPa). Approximately equal to average atmospheric pressure at sea level (1.01325 bar = 1 atm). Common in Europe and for industrial/hydraulic applications. kPa (kilopascal) - Metric unit, 1000 Pascals. Part of the SI system. 100 kPa = 1 bar. Used in scientific and engineering contexts worldwide. Relationships: 1 bar = 100 kPa = 14.5 PSI, 1 PSI = 6.895 kPa = 0.06895 bar, 1 kPa = 0.145 PSI = 0.01 bar, 1 atm = 14.7 PSI = 101.3 kPa = 1.013 bar. Most countries have standardized on bar or kPa, with the US primarily using PSI.
Atmospheric pressure is the pressure exerted by Earth's atmosphere due to gravity pulling air downward. At sea level: 1 standard atmosphere (atm) = 14.696 PSI = 101.325 kPa = 1.01325 bar = 760 mmHg (Torr). This is called 'standard atmospheric pressure' or '1 atm'. Why it matters: Weather patterns - High pressure brings clear skies, low pressure brings precipitation. Altitude effects - Pressure decreases with altitude (about 1 PSI per 2,000 feet). Vacuum systems - Vacuum is measured relative to atmospheric pressure. Hydraulic systems - 'Gauge pressure' measures above atmospheric, 'absolute pressure' includes atmospheric. Human body - We don't feel 14.7 PSI because it's balanced inside and outside. Measurement units: Barometers measure atmospheric pressure in inches of mercury (inHg) or millibars (mb). 1 mb = 1 hPa = 0.1 kPa. Our converter handles all atmospheric pressure conversions.
Tire pressure conversion for common vehicles: Car tires (typical): 32 PSI = 2.2 bar = 220 kPa, 35 PSI = 2.4 bar = 241 kPa, 36 PSI = 2.5 bar = 248 kPa. SUV/Light truck: 35 PSI = 2.4 bar = 241 kPa, 38 PSI = 2.6 bar = 262 kPa, 40 PSI = 2.8 bar = 276 kPa. Heavy vehicles: 50 PSI = 3.4 bar = 345 kPa, 80 PSI = 5.5 bar = 552 kPa, 100 PSI = 6.9 bar = 689 kPa. Bicycle tires (high pressure): 80 PSI = 5.5 bar = 552 kPa, 100 PSI = 6.9 bar = 689 kPa, 120 PSI = 8.3 bar = 827 kPa. Conversion tips: Always check your vehicle's door jamb or manual for recommended pressure. Weather affects tire pressure - about 1 PSI change per 10°F. European cars use bar, US cars use PSI, Asian cars may use either. Our converter helps you check pressure regardless of the gauge units. Never exceed maximum tire pressure ratings.
Vacuum pressure is pressure below atmospheric pressure (less than 14.7 PSI or 1 atm at sea level). It's measured as negative gauge pressure or positive absolute pressure below atmospheric. Measurement units for vacuum: Inches of Mercury (inHg) - Most common in HVAC and automotive in the US. Standard atmospheric = 29.92 inHg. Perfect vacuum = 0 inHg. Millimeters of Mercury (mmHg or Torr) - Scientific and medical (blood pressure). Standard atmosphere = 760 mmHg. PSI vacuum - Measured as 'inches of Hg vacuum' (29.92 minus reading). Perfect vacuum = 29.92 inHg. Bar or millibar - European vacuum measurements. 1 mbar = 1 hPa. Common vacuum levels: Rough/Low vacuum: 0-27 inHg (automotive brake boosters typically 18-22 inHg). Medium vacuum: 27-29 inHg (many industrial processes). High vacuum: 29-29.9 inHg (scientific equipment). Ultra-high vacuum: approaching 29.92 inHg (space simulation). Conversion: 1 inHg = 25.4 mmHg = 0.491 PSI. Our converter handles vacuum conversions across all common units.
Hydraulic systems use various pressure units depending on region and application: Industrial hydraulics: Low pressure: 10-50 bar (145-725 PSI) - Used for simple actuation. Medium pressure: 50-150 bar (725-2,175 PSI) - Standard industrial hydraulics. High pressure: 150-300 bar (2,175-4,350 PSI) - Mobile equipment, presses. Very high pressure: 300-700 bar (4,350-10,150 PSI) - Heavy machinery, braking systems. Common hydraulic conversions: 100 bar = 1,450 PSI = 10 MPa (common industrial standard), 200 bar = 2,900 PSI = 20 MPa (heavy machinery), 350 bar = 5,075 PSI = 35 MPa (high-pressure systems), 10 PSI = 0.69 bar = 0.069 MPa (pneumatics). Key considerations: Hydraulic systems rated for specific maximum pressures. Always use proper hoses and fittings rated for system pressure. High-pressure hydraulics can be dangerous - use caution and proper safety equipment. Our converter helps with hydraulic pressure conversions. Remember: 1 MPa (megapascal) = 10 bar = 145 PSI.
Gauge pressure and absolute pressure differ by the atmospheric pressure reference: Gauge pressure - Measures pressure relative to atmospheric pressure. What most pressure gauges show. Reads 0 at atmospheric pressure. Example: Tire pressure is gauge pressure. If gauge shows 30 PSI, actual pressure is 30 PSI above atmosphere (30 + 14.7 = 44.7 PSI absolute). Absolute pressure - Measures pressure relative to perfect vacuum. Includes atmospheric pressure. Used for scientific calculations and some industrial applications. At sea level, atmospheric pressure is about 14.7 PSI absolute (or 1 atm). Conversions: Absolute = Gauge + Atmospheric. Gauge = Absolute - Atmospheric. Practical examples: Tire at 30 PSI (gauge) = 44.7 PSI absolute, Atmospheric pressure = 0 PSI gauge = 14.7 PSI absolute, Perfect vacuum = -14.7 PSI gauge = 0 PSI absolute, Scuba tank at 3,000 PSI (gauge) = 3,014.7 PSI absolute. Most everyday measurements use gauge pressure (tires, air compressors, hydraulics). Absolute pressure is used in scientific contexts, gas laws, and some specialized engineering.
Steam and boiler pressure require specific considerations for safety and efficiency: Steam pressure classifications: Low-pressure steam: Below 15 PSI (1 bar) - Used for heating, humidification. Medium-pressure steam: 15-150 PSI (1-10 bar) - Industrial processes, some heating. High-pressure steam: Above 150 PSI (>10 bar) - Power generation, specific industrial uses. Common conversions for steam systems: 5 PSI = 0.34 bar = 34 kPa (typical residential steam heat), 15 PSI = 1.03 bar = 103 kPa (common low-pressure limit), 100 PSI = 6.9 bar = 689 kPa (medium industrial systems), 600 PSI = 41 bar = 4,136 kPa (power plant operations). Safety important notes: Steam systems are dangerous - pressure vessels require certification. Boiler pressure relief valves are critical safety devices. Steam pressure relates to temperature (higher pressure = higher temperature). 100 PSI steam = approximately 338°F (170°C). Our converter helps with pressure unit conversions, but steam systems require professional expertise. Pressure gauges on boilers typically show PSI or bar.