Bar to PSI Converter

One bar is 14.5038 psi:

psi = bar × 14.503774

The convenient anchor is that one bar is roughly one atmosphere — precisely, 1 atm is 1.01325 bar. So a reading in bar is close to "how many atmospheres above vacuum", which is why the unit stuck in Europe.

Everyday pressures:

• 2.0 bar → 29.0 psi
• 2.2 bar → 31.9 psi — a common car tyre pressure
• 2.5 bar → 36.3 psi
• 3.0 bar → 43.5 psi — a loaded van
• 9 bar → 130.5 psi — espresso extraction
• 200 bar → 2,900.8 psi — a full scuba cylinder
• 300 bar → 4,351.1 psi — a high-pressure diving cylinder

Diving is where the conversion is most safety-critical. European cylinders are filled to 200 or 300 bar; American ones are rated in psi, commonly 3,000 psi (206.8 bar). A regulator or cylinder rated for 3,000 psi must not be filled to 300 bar, which is 4,351 psi — 45% over its rating.

Pressure washers are marketed in bar in Europe and psi in the US. A 150 bar domestic machine is 2,175 psi; a "2,000 psi" American unit is 137.9 bar. Comparing across markets without converting makes one look far more capable than it is.

Weather uses a different scale again: atmospheric pressure is reported in hectopascals or millibars, where 1 bar = 1,000 mbar = 1,000 hPa. A 1,013 hPa reading is 1.013 bar, or 14.7 psi.

For a rough figure, multiply bar by 14.5.