Bar to Pounds per Square Inch

Bar and pounds per square inch

The bar is exactly 100,000 pascals, slightly less than one standard atmosphere. Tire pressure in Europe, espresso machines, scuba tanks and industrial gauges use bar.

One psi is the pressure of one pound-force on one square inch: about 6,894.757 pascals, derived from exact definitions. Tire pressure in the US and UK, air compressors, pressure washers and plumbing use psi.

Worked example

Convert 2.2 bar: 2.2 × 14.50377377 = 31.9083023, so 2.2 bar is 31.9083023 pounds per square inch. Likewise 2 bar = 29.00754755 psi.

Estimating in your head

Multiply by 15 for a quick figure; it is off by about 3.4%. For 2.2 bar that gives 33 psi, against 31.9083 exactly.

Going the other way

To convert pounds per square inch to bar, divide by 14.50377377 (or multiply by 0.0689475729317). The swap button between the boxes opens that page.

psi = bar × 14.50377377

1 bar = 100,000 Pa and 1 psi = ≈ 6,894.757293 Pa, both by definition, so the factor is their ratio: 14.50377377 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.