bar to psi

European-made pressure gauges and tools, common on imported air compressors and some tire gauges, read in bar, which needs converting for anyone used to the psi figures printed on US vehicle doorjambs. A typical passenger car tire specified at 2.2 bar corresponds to about 32 psi, worth checking against the sticker before trusting an imported gauge's reading outright, since even a small bar-reading error translates into a noticeable psi gap once converted.

Pressure washers bring up the same pair from a different angle: models built for European markets list cleaning power in bar, while US retail models are almost always rated in psi. Comparing a "150 bar" import against a "2,000 psi" domestic model means converting one figure into the other's unit first, otherwise the two numbers look impossible to compare at a glance despite describing similar machines.

To convert bar to pounds-force per square inch, multiply by 14.50377377:

psi = bar × 14.50377377

Roughly atmospheric pressure, 1 bar, equals about 14.50 psi. A passenger car tire rated at 2.2 bar converts to roughly 31.91 psi. A heavy-duty 150-bar pressure washer works out to about 2,175.57 psi.

The factor is simply the reciprocal of the psi-to-bar factor. Consumer pressure gauges rarely display fractional psi, so rounding to the nearest whole psi is usually all the precision that's needed in practice.

The common mistake is using the loose mental shortcut "1 bar ≈ 10 psi" and stopping there. That shortcut understates real pressure by close to a third, since the actual factor is closer to 14.5 — fine for a glance, risky for anything that needs to be accurate, like topping off a tire.

A scuba diving regulator rated to handle 300 bar tank pressure, common for high-capacity steel tanks, converts to about 4,351.13 psi, a figure closer to what a US-trained diver would expect to see printed on an American-filled cylinder, and worth checking before assuming an imported regulator is rated for a domestic tank.