PSI Converter

PSI (pounds per square inch) conversions: 1 PSI = 0.0689476 bar. 1 PSI = 6.89476 kPa (kilopascals). 1 PSI = 0.068046 atm (atmospheres). 1 PSI = 51.7149 mmHg (torr). 1 PSI = 2.03602 inHg. Examples: 30 PSI (tire) = 2.07 bar = 206.8 kPa. 14.7 PSI (sea level) = 1 atm = 101.325 kPa = 1.01325 bar. Most common: PSI to bar for European specs, PSI to kPa for scientific use.

Recommended tire pressure varies by vehicle: Passenger cars: 30-35 PSI (2.0-2.4 bar) typical. SUVs/Trucks: 35-45 PSI (2.4-3.1 bar). Performance cars: 32-40 PSI (2.2-2.8 bar). Motorcycles: 28-40 PSI front, 32-42 PSI rear. Bicycles: 40-65 PSI (road), 30-50 PSI (mountain). Find exact pressure: Driver door jamb sticker, owner's manual, gas cap. Check when tires cold (before driving). Under-inflation: Poor fuel economy, tire wear. Over-inflation: Harsh ride, center wear. Check monthly, adjust seasonally (1 PSI change per 10°F).

PSI = Pounds per Square Inch, measures pressure (force per area). Common applications: Tires: Proper PSI ensures safety, fuel efficiency, tire life. Wrong pressure = blowouts, poor handling. Air compressors: Tool requirements (impact wrench: 90 PSI, spray gun: 30-50 PSI). Hydraulics: High PSI for heavy machinery (1000-5000 PSI). Water pressure: Home water: 40-60 PSI. Pressure washing: 1000-3000 PSI. Pneumatic systems: Industrial equipment, HVAC. Measuring PSI: Use pressure gauge. Digital gauges most accurate (±0.5 PSI).

Pressure unit comparison: PSI (Imperial): Common in USA for tires, tools. Easy to visualize (14.7 PSI = atmospheric pressure at sea level). Bar (Metric): Common in Europe/Asia. 1 bar ≈ atmospheric pressure. Easy mental math (30 PSI ≈ 2 bar). kPa (SI unit): Scientific standard. 100 kPa ≈ 1 bar. Quick conversions: 30 PSI = 2.07 bar = 207 kPa. 50 PSI = 3.45 bar = 345 kPa. 100 PSI = 6.89 bar = 689 kPa. Why different units: PSI historical in US. Bar/kPa international standard. Converting necessary for: Imported vehicles, international specs, scientific work.

PSI vs PSIG: PSI (absolute pressure): Measured from perfect vacuum (0 PSI = no pressure at all). Used in scientific calculations. PSIG (gauge pressure): Measured from atmospheric pressure (0 PSIG = normal air pressure, 14.7 PSI absolute). Used for tire gauges, compressors, practical applications. Relationship: PSI (absolute) = PSIG + 14.7. Example: Tire gauge shows 32 PSIG. Absolute pressure = 32 + 14.7 = 46.7 PSI. Most everyday pressure = PSIG. "PSI" often means PSIG in practice. Why it matters: Tire inflators show PSIG. Specs usually list PSIG. Negative PSIG = vacuum.

PSI accuracy requirements by application: Tires: ±1 PSI acceptable. 2-3 PSI off affects performance. Digital gauge recommended ($10-30). Racing/Performance: ±0.5 PSI critical. Temperature affects pressure (up 1 PSI per 10°F). Professional gauges needed. Air tools: ±5 PSI usually fine. Regulators maintain pressure. Industrial hydraulics: ±2% tolerance typical. Safety critical. Calibrated gauges required. Types of gauges: Pencil: ±3 PSI, cheap ($2-5). Dial: ±1-2 PSI, durable ($15-40). Digital: ±0.5 PSI, precise ($20-100). When to check: Tires monthly and before trips. Tools before critical work. Calibrate gauges yearly.

Reference PSI values: Atmospheric: 14.7 PSI (sea level, 1 atm). Car tires: 30-35 PSI (cold). Truck tires: 35-80 PSI (depends on load). Bike tires: 40-65 PSI (road), 25-40 PSI (mountain). Basketball: 7-9 PSI. Soccer ball: 8-16 PSI. Air compressor output: 90-150 PSI typical. Air tools: Impact wrench: 90 PSI. Spray gun: 30-50 PSI. Nail gun: 70-120 PSI. Water pressure: Home: 40-60 PSI. Pressure washer: 1000-4000 PSI. Scuba tank: 3000-4500 PSI. Hydraulic systems: 1000-5000 PSI. Fire hose: 150-300 PSI. These values help estimate and verify readings.