Convert pressure between PSI, kPa, bar, atm, mmHg, inHg, and more. Calculate force on area and water depth equivalent with reference table.
Pounds per square inch (PSI) is the most widely used pressure unit in US engineering, from tire pressures and hydraulic systems to scuba tank ratings and blood pressure. Converting between PSI, kPa, bar, atmosphere, mmHg, and other units is a daily task in engineering and science.
This comprehensive converter handles all common pressure units: PSI, kPa, MPa, bar, atm, mmHg (Torr), inHg, inH₂O, and millibar. Enter a value in any unit and instantly see the equivalent in all others. It also computes the force exerted on a given area and the equivalent water column depth.
Preset buttons load common reference pressures: tire pressure (32 PSI), scuba tank (3000 PSI), hydraulic system (5000 PSI), standard atmosphere (14.696 PSI), 1 bar, and blood pressure (120 mmHg). A conversion table provides quick lookups for common values.
The calculator is essential for mechanical engineers, HVAC technicians, medical professionals, divers, and anyone working with pressure measurements in mixed US/metric environments.
Pressure unit conversion errors between US customary (PSI) and SI (kPa, bar) are among the most common engineering mistakes. This converter shows all units simultaneously.
The force-on-area calculation is invaluable for seal design, cylinder sizing, and load analysis. Seeing the conversions side by side makes it easier to spot when a number is gauge pressure, absolute pressure, or just a rounded reference value.
1 PSI = 6.8948 kPa = 0.06895 bar = 0.06805 atm = 51.715 mmHg. 1 atm = 14.696 PSI = 101.325 kPa = 760 mmHg. Force = Pressure × Area. Water depth = P / (ρg) = P / 9790.
Result: 101.325 kPa, 1.01325 bar, 1 atm, 760 mmHg, 29.92 inHg
Standard atmospheric pressure. 14.696 × 6.8948 = 101.325 kPa. This is the pressure exerted by a 760 mm column of mercury or a 10.33 m column of water.
PSI is a convenient working unit in mechanical systems, but it is only one point on a wider scale that includes bar, atm, kPa, mmHg, and head-pressure units. Converting between them helps when a spec sheet, gauge, and control system do not use the same unit.
The most common mistake is mixing PSI gauge and PSI absolute. Gauge pressure is relative to atmosphere; absolute pressure includes atmosphere. The conversion table and reference notes in this calculator are meant to make that distinction visible before the number is used in a design or report.
Use this calculator when checking tire pressure, hydraulic pressure, or medical and meteorological values that are reported in different unit systems. The extra force and water-head outputs help translate the pressure into a physical quantity people can sanity-check.
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PSIA is absolute pressure (including atmospheric). PSIG is gauge pressure (relative to atmosphere). PSIA = PSIG + 14.696. A tire at 32 PSIG is 46.7 PSIA.
mmHg (also called Torr) is used for blood pressure, vacuum systems, and meteorology. Normal blood pressure is 120/80 mmHg = 15.9/10.6 kPa.
Almost but not quite. 1 bar = 100 kPa, while 1 atm = 101.325 kPa. The difference is about 1.3%. In practice, they are often treated as equivalent for rough calculations.
Divers use bars or PSI for tank pressure, and atmospheres (ATA) for depth pressure. Every 10 meters of seawater adds about 1 atmosphere (14.7 PSI).
Weather reports use millibars (hPa) or inHg. Standard: 1013.25 mbar = 29.92 inHg = 14.696 PSI. Low pressure (storm): ~980 mbar. High pressure: ~1030 mbar.
Ultra-high pressure water jets operate at 60,000-90,000 PSI (4,000-6,000 bar). Diamond anvil cells in research reach millions of PSI.