Bar to PSI Calculator

One bar equals approximately 14.5038 PSI (pounds per square inch), and this calculator converts any pressure reading between these two widely used units instantly. Bar is the standard metric pressure unit used across Europe, in most engineering contexts, and in scientific instrumentation. PSI is the dominant imperial unit in the United States, appearing on tire pressure gauges, hydraulic system specs, pressure cookers, and compressed air equipment. Whenever you encounter a specification written in bar — perhaps on a European bicycle pump, a pneumatic tool's data sheet, or a boiler pressure gauge — and need to understand it in PSI terms, this converter provides the answer immediately. Conversely, if you are working with a US-sourced pressure reading and need to match it to a metric specification, the reverse calculation is equally straightforward. Common reference points: car tires typically run at 2.2–2.6 bar (32–38 PSI), road bicycle tires at 6–9 bar (87–130 PSI), and household water pressure at 1.5–3 bar (22–44 PSI).

The formula is: PSI = bar × 14.5038. This conversion factor is derived from the SI definitions of both units. One bar is defined as exactly 100,000 Pascals (Pa). One PSI is defined as one pound-force per square inch, which equals exactly 6,894.757 Pa under the international definition of the pound-force and the inch. Dividing 100,000 Pa per bar by 6,894.757 Pa per PSI yields 14.5038 PSI per bar, rounded to four decimal places. The full precision value is 14.503773773... and continues as a repeating decimal, so the commonly used 14.5038 introduces an error of less than 0.001% — negligible for any practical application. For example, 2.5 bar equals 2.5 × 14.5038 = 36.2595 PSI. Note that bar and atmosphere (atm) are related but not identical: 1 atm = 1.01325 bar, so atmospheric pressure is about 14.696 PSI rather than exactly 14.5038 PSI.