Convert Pascal to Pound per Square Inch (Pa → psi)

Converting pascals 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 pascals

   Start with the number of pascals (Pa) you want to convert.
2. 2
   Multiply by 0.000145

   The conversion factor from Pa to psi is 0.000145. 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 pascals by 0.000145. For the reverse direction, multiply by 6,894.7573.

• ✓1 Pa = 1 N/m².
• ✓1 kPa = 1000 Pa; 1 MPa = 1,000,000 Pa; 1 bar = 100,000 Pa.
• ✓Use kPa, MPa or bar for practical engineering work.

• ✗Confusing Pa with psi — 1 psi = 6895 Pa.
• ✗Using Pa for tyre pressures — 220,000 Pa unwieldy; use 2.2 bar.
• ✗Mixing Pa absolute and Pa gauge without specification.

What is the Pascal?

The pascal is the SI unit of pressure, equal to 1 newton per square meter (1 N/m²). Named after French mathematician and physicist Blaise Pascal (1623–1662), it became the SI standard in 1971. One pascal is a very small pressure: atmospheric pressure at sea level is about 101,325 Pa, the human breath exerts roughly 100 Pa above ambient, and tire pressure is in the hundreds of thousands of pascals. Because the pascal is small, the kilopascal (1 kPa = 1,000 Pa), megapascal (1 MPa = 10⁶ Pa), and gigapascal (1 GPa = 10⁹ Pa) are more commonly used in practice. Modern weather forecasts use hectopascals (1 hPa = 100 Pa = 1 millibar). The pascal relates to the bar (1 bar = 100,000 Pa), the psi (1 psi ≈ 6,895 Pa), the atmosphere (1 atm = 101,325 Pa), and mmHg (1 mmHg ≈ 133.3 Pa). Scientific and engineering publications use the pascal universally.

• Scientific and engineering calculations
• Ventilation and HVAC airflow pressures
• Acoustic pressure (sound) measurements

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