Convert Pound per Square Inch to Atmosphere (psi → atm)

Converting psi to atmospheres is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in psi

   Start with the number of psi (psi) you want to convert.
2. 2
   Multiply by 0.068046

   The conversion factor from psi to atm is 0.068046. Multiply your value by this number.
3. 3
   Read the result in atmospheres

   The result is your value in atmospheres (atm).

Multiply the value in psi by 0.068046. For the reverse direction, multiply by 14.695949.

• ✓1 psi ≈ 6.9 kPa = 0.069 bar.
• ✓14.7 psi = 1 atm = 1.01 bar.
• ✓Most US pressure gauges show psi.

• ✗Setting a European tyre at 35 bar instead of 35 psi — disaster.
• ✗Confusing psi (gauge) with psia (absolute).
• ✗Using psi in scientific papers — prefer Pa or MPa.

What is the Pound per Square Inch?

Pounds per square inch (psi) equals approximately 6,895 pascals and is the standard pressure unit in American tire pressures, hydraulics, and gas-cylinder specifications. American car tires are typically inflated to 30–35 psi, household water systems run at 40–60 psi, and scuba tanks are filled to 3,000 psi (about 200 bar). The psi is essential in American engineering for stress calculations, hydraulic systems, and pneumatic equipment. Two variants exist: 'psig' (gauge, measured above atmospheric) and 'psia' (absolute, including atmosphere) — gauge is the default unless specified. The psi relates to the pascal (1 psi ≈ 6,895 Pa), the kilopascal (1 psi ≈ 6.895 kPa), the bar (14.504 psi = 1 bar), the atmosphere (14.696 psi = 1 atm), and the inch of mercury (1 inHg ≈ 0.491 psi). Outside the US, kPa or bar dominate.

• US tyre pressures
• US plumbing and water system specs
• US compressed-air tool ratings

What is the Atmosphere?

The atmosphere equals exactly 101,325 pascals (the average atmospheric pressure at sea level, latitude 45°) and is a reference unit in chemistry, diving, and engineering. Defined for scientific convenience to represent 'standard atmospheric pressure,' it is widely used in chemistry (gas laws, reaction conditions), aviation (cabin pressure relative to ambient), and scuba diving (depth pressure: every 10 m of seawater adds about 1 atm). Standard reference conditions in chemistry often specify 1 atm and 25°C. The atmosphere relates to the pascal (101,325 Pa = 1 atm), the kilopascal (101.325 kPa = 1 atm), the bar (1.01325 bar = 1 atm), the psi (14.696 psi = 1 atm), the torr (760 torr = 1 atm), and the meter of seawater (10.33 mH₂O = 1 atm). The 'technical atmosphere' (1 at = 98.066 kPa = 1 kgf/cm²) is a slightly different historical unit no longer in use.

• Chemistry standard conditions
• Aviation cockpit pressurisation references
• Pressure tank and vessel ratings