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

Converting atmospheres to psi 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 atmospheres

   Start with the number of atmospheres (atm) you want to convert.
2. 2
   Multiply by 14.695949

   The conversion factor from atm to psi is 14.695949. Multiply your value by this number.
3. 3
   Read the result in psi

   The result is your value in psi (psi).

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

• ✓1 atm = 101,325 Pa = 1.01325 bar = 14.696 psi.
• ✓Note: atm ≠ bar. Close but not identical.
• ✓Modern SI prefers pascals; atm is a legacy reference.

• ✗Using 1 atm = 1 bar exactly — off by 1.3%.
• ✗Confusing standard atm with technical atmosphere (98,066.5 Pa) or atmosphere-absolute in diving.
• ✗Applying 1 atm outside sea level without correction.

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

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