PSI to Bar
Convert any value from psi to bar with full precision. Use the converter above for instant results, or read on for the exact formula, worked examples, common uses, and answers to frequently asked questions.
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About the PSI to Bar conversion
Pressure conversions are used in physics, engineering, medicine, meteorology, and many industrial processes. The SI unit is the pascal, but bar, psi (pounds per square inch), atmospheres, torr, and mmHg are common in their respective fields.
This page focuses specifically on converting psi to bar. Use the converter above for instant results, or read on for what each unit is, the exact formula, a worked example, and answers to common questions.
Understanding psi and bar
What is a psi?
Pounds per square inch, or psi, is one pound-force spread over one square inch, about 6,895 pascals. It is the standard pressure unit in the United States for tires, compressors, and hydraulics.
What is a bar?
The bar equals 100,000 pascals and is very close to average atmospheric pressure at sea level. It is common in weather reporting, scuba diving, and industrial pressure gauges.
How a psi compares to a bar
The bar is the larger of the two units: it takes about 14.50377377 psi to make a single bar. Because the psi is smaller, the same length or quantity works out to a larger number when you measure it with that unit. Knowing which unit is larger is a quick way to sanity-check a conversion: if the numbers move in the wrong direction, the two units have probably been swapped.
Conversion formula
The exact mathematical relationship between psi and bar is:
1 psi = 0.06894757 bar
So to convert a value V from psi to bar, use:
Vbar = Vpsi × 0.06894757
To go in the opposite direction:
Vpsi = Vbar × 14.50377377
These factors come from the international definitions published by NIST, BIPM, and ISO 80000 and are exact within their respective standard systems. The converter applies them with full floating-point precision.
Worked example
Using the formula above, here are some common values converted from PSI to Bar:
| PSI | Bar |
|---|---|
| 1 | 0.068948 |
| 5 | 0.344738 |
| 10 | 0.689476 |
| 25 | 1.723689 |
| 50 | 3.447379 |
| 100 | 6.894757 |
Sources and accuracy
The pascal equals one newton per square meter (BIPM, NIST). Standard atmospheric pressure equals exactly 101,325 Pa. One bar equals exactly 100,000 Pa. One psi equals exactly 6,894.757293168 Pa. One torr equals exactly 101,325 / 760 Pa.
Conversion factors are cross-checked against the NIST SP 811 guide, the BIPM SI brochure, and ISO 80000, plus published historical references for older unit systems. For mission-critical work such as medical dosing, legal-for-trade measurement, aerospace, or large-scale engineering, always verify independently with the original source.
Practical tips
When reading weather reports, "millibars" and "hectopascals" are the same unit (1 mbar = 1 hPa = 100 Pa). Standard sea-level pressure is 1013.25 mbar or hPa.
Frequently asked questions
How many bar are in one psi?
One psi equals 0.06894757 bar. To convert, multiply your psi value by 0.06894757.
Which is bigger, a psi or a bar?
The bar is bigger. One psi is only about 0.06894757 bar.
How accurate is this psi to bar converter?
It uses the official international conversion factors from NIST and BIPM with full double-precision floating-point accuracy. For everyday use the result is precise to many more decimal places than any practical measurement requires.
Can I convert bar back to psi as well?
Yes. Use the swap button above to reverse the From and To fields, or change either dropdown to any unit in the pressure category. The calculation runs entirely in your browser, so it also works offline once the page has loaded.