BCBetter Calculators

Bar to PSI Calculator

Convert pressure in bar to pounds per square inch (PSI) instantly.

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Enter your values and click Calculate

How It Works

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.

Examples

2 bar
Typical mountain bike tyre pressure.
Result: 2 bar ≈ 29.0076 PSI
2.5 bar
Typical car tyre inflation pressure.
Result: 2.5 bar ≈ 36.2595 PSI
8 bar
Road bicycle tyre (high-pressure clincher).
Result: 8 bar ≈ 116.030 PSI

Frequently Asked Questions

Is bar the same as atmosphere?
Close but not identical. One standard atmosphere (atm) equals exactly 1.01325 bar. At sea level, atmospheric pressure is therefore about 14.696 PSI rather than 14.5038 PSI. For most engineering and tire-pressure applications the difference is negligible, but scientific work should use the correct unit for the context.
What is PSI?
PSI stands for pounds per square inch, the most common pressure unit in the United States. It measures the force in pounds applied over one square inch of surface area. It is used for tire pressure, hydraulic systems, pressure testing, and compressed gas cylinders, among many other applications.
Why does my tire gauge show different values from online specs?
Pressure gauges typically measure gauge pressure (relative to atmospheric pressure), while some specifications reference absolute pressure (which includes atmospheric pressure). Most tire and bicycle pump contexts use gauge pressure, so as long as both your gauge and the specification use the same reference, the bar-to-PSI conversion applies directly.

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