Convert bar to pounds per square inch

One bar is 14.5037738 pounds per square inch. To convert any amount, multiply by 14.5037738. Going the other way, one pound per square inch is 0.0689475729 bar.

Multiply the bar figure by 14.5037738. So psi = bar × 14.5037738. For a quick mental estimate, multiplying by about 14.5 gets you within a percent or so, which is close enough for most everyday purposes.

One bar is roughly atmospheric pressure at sea level. One bar is exactly 100,000 pascals, chosen to be close to average atmospheric pressure at sea level. It is the common unit for tyre and diving pressures in Europe.

One pound per square inch is a car tyre runs about 32 psi. Psi is the tyre-pressure unit in North America. Car tyres typically run 30–35 psi, and getting this wrong measurably affects both fuel economy and braking distance.

Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding bar before converting introduces an error the conversion then multiplies.