How to use this calculator
Enter a pressure value in bar into the field above and press Calculate. The tool multiplies your value by the exact conversion factor to return the equivalent pressure in psi (pounds per square inch), and also shows the equivalent in kilopascals for reference. Press Reset to return to the default value of 1 bar.
The bar to psi formula
Bar and psi are both units of pressure, but they come from different measurement systems. One bar is defined as exactly 100,000 pascals (100 kPa), a round number in the metric system originally chosen to approximate normal atmospheric pressure. One psi is defined as one pound-force applied over an area of one square inch, an imperial/US customary unit. The exact conversion factor between them is:
1 bar = 14.5037738 psi
To convert bar to psi, multiply the bar value by 14.5037738. For example, 2 bar × 14.5037738 = 29.0075476 psi. To go the other direction, divide the psi value by 14.5037738 (equivalently, multiply by approximately 0.0689476) to get bar. This calculator also reports the kilopascal equivalent using 1 bar = 100 kPa, since kPa is another common pressure unit seen on gauges and spec sheets alongside psi.
Why this conversion is needed
Pressure gauges, tire inflators, tools, and industrial equipment are labeled in different units depending on where they were manufactured and which measurement system is standard in that industry or region. Bar is common on European and Asian equipment, scuba and diving gear, and many pressure washers and compressors, while psi dominates on tire pressure placards, plumbing fixtures, and hydraulic equipment in the United States. Anyone working across both systems, such as mechanics, HVAC technicians, scuba divers, or engineers reading equipment rated in bar but installing it in a psi-labeled system, needs a fast and accurate way to move between the two units without rounding errors compounding.
Reference points worth memorizing
A few benchmark values make it easier to sanity-check any conversion: standard atmospheric pressure at sea level is 1 atm = 1.01325 bar = 14.6959 psi, which is why 1 bar (14.5 psi) is very close to, but not exactly, one atmosphere. A typical passenger car tire is inflated to roughly 2.2 to 2.5 bar, which is about 32 to 36 psi. A road bike tire commonly runs 6 to 8 bar (87 to 116 psi), much higher than a car tire because of its narrow contact area. Home water pressure is usually delivered around 3 to 5 bar (43 to 73 psi), and a residential pressure washer often produces 100 to 150 bar (1,450 to 2,175 psi) for cleaning tasks.
Worked examples
1 bar = 14.5037738 psi (the base conversion factor itself). 2.5 bar (a typical car tire target) = 2.5 × 14.5037738 = 36.259 psi. 10 bar (a common rating for compressor tanks) = 10 × 14.5037738 = 145.038 psi. 0.5 bar = 0.5 × 14.5037738 = 7.252 psi. In each case the calculator performs the same single multiplication, so results are exact to the precision shown, not estimates or ranges.
Frequently asked questions
Is 1 bar the same as 1 atmosphere? No, they are close but not identical. 1 atmosphere (atm) equals 1.01325 bar, or 14.6959 psi, while 1 bar equals 14.5037738 psi. The difference is small (about 1.3%) but matters in precise engineering or scientific work.
How do I convert psi back to bar? Divide the psi value by 14.5037738, or multiply by 0.0689476. For example, 30 psi ÷ 14.5037738 = 2.0685 bar.
Why is the conversion factor 14.5037738 and not a rounder number? It comes directly from the definitions of the two units: 1 bar = 100,000 pascals, and 1 psi = 6,894.75729 pascals (1 pound-force per square inch, using standard gravity and the international pound). Dividing 100,000 by 6,894.75729 gives 14.5037738, which is why the factor has many decimal places rather than being a clean whole number.
What is a millibar in psi? A millibar (mbar) is 1/1000 of a bar, commonly used in meteorology for atmospheric pressure readings. 1 mbar = 0.0145037738 psi.
Where will I see bar versus psi in everyday life? Bar appears on European car and bike tire gauges, scuba tank and regulator ratings, and many pressure cooker and pressure washer specs. Psi appears on US tire placards, plumbing and irrigation fittings, bicycle pumps sold in the US, and most American hydraulic and pneumatic tool ratings.