Convert Bar to PSI – Pressure Converter
This tool converts pressure values from bar to pounds per square inch (psi) using the internationally recognized relationship between metric and imperial pressure units. It is intended for quick, reliable unit conversion where the units themselves are equivalent (for example, converting a recorded gauge reading in bar to the same reading expressed in psi).
Use this converter for engineering checks, documentation, setpoints, and routine calculations. It does not change the reference frame of a measurement (gauge vs absolute); if you need to convert between gauge and absolute pressure you must add or subtract the appropriate reference pressure (for example atmospheric pressure) before or after the unit conversion.
Conversion accuracy follows published unit definitions; for traceable measurement and calibration tasks consult relevant standards and accredited laboratories to determine required uncertainty and number of significant digits.
Interactive Converter
Convert between bar and psi (pounds per square inch) with precision rounding.
Quick reference table
| Bar | PSI (Pounds per Square Inch) |
|---|---|
| 1 bar | 14.5 psi |
| 5 bar | 72.52 psi |
| 10 bar | 145.04 psi |
| 25 bar | 362.59 psi |
| 50 bar | 725.19 psi |
| 100 bar | 1,450.38 psi |
Methodology
The conversion uses fixed SI definitions: 1 bar = 100000 pascals (Pa). The pound-force per square inch (psi) is defined via the pascal using the international avoirdupois pound and inch, yielding the exact conversion factor applied here.
For practical use we apply the factor psi = bar × 14.503773773022, which is derived from 100000 Pa ÷ 6894.757293168 Pa per psi. Results are numerical conversions only and do not alter the measurement reference (gauge vs absolute).
When conversions are used in safety-critical or regulatory contexts, follow calibration traceability and uncertainty practices described by national and international standards (for example NIST guidance, ISO 80000-1 for quantities and units, and ISO/IEC 17025 for laboratory calibration competence).
Worked examples
1 bar = 14.503773773022 psi → commonly shown as 14.5037738 psi when rounded to 7 decimal places.
2.5 bar = 2.5 × 14.503773773022 = 36.259434432555 psi → round to 36.2594344 psi for 7 decimals or 36.26 psi for two decimals.
0.5 bar = 7.251886886511 psi → round to 7.251887 psi for 6 decimal places.
Key takeaways
This converter applies the exact, fixed relationship between bar and psi via pascals: multiply bar by 14.503773773022 to obtain psi.
Verify whether your pressure is gauge or absolute before using values for safety, control setpoints, or regulatory reporting; follow calibration and traceability standards for high-accuracy needs.
Expert Q&A
What is the exact conversion factor from bar to psi?
The exact factor used is 1 bar = 14.503773773022 psi, based on 1 bar = 100000 Pa and 1 psi = 6894.757293168 Pa.
Does this converter handle gauge vs absolute pressure?
No. The unit conversion itself is independent of reference frame. To convert gauge to absolute pressure you must add atmospheric pressure (approximately 1.01325 bar at sea level) before or after unit conversion as appropriate.
How many decimal places should I display?
Choose decimal places to reflect the measurement uncertainty. For engineering displays two to three significant decimals are common; for calibration traceability use the number of digits supported by instrument uncertainty and lab certificates as described in ISO/IEC 17025.
What accuracy can I expect from this mathematical conversion?
The mathematical conversion is exact to the precision of the factor. Real-world accuracy is limited by the instrument's measurement uncertainty, environmental factors, and calibration. For traceable accuracy, rely on calibrated instruments and accredited labs.
Where should I go for calibration and traceability of pressure instruments?
Seek an ISO/IEC 17025 accredited calibration laboratory and follow national metrology guidance (for example via NIST or equivalent national institutes) for documentation and traceability.
Sources & citations
- NIST — SI Units and Quantity Names — https://www.nist.gov/pml/weights-and-measures/si-units
- NIST — Pressure Units (NIST Reference on Constants, Units, and Uncertainty) — https://physics.nist.gov/cuu/Units/pressure.html
- ISO 80000-1 — Quantities and units — https://www.iso.org/standard/30669.html
- ISO/IEC 17025 — General requirements for the competence of testing and calibration laboratories — https://www.iso.org/standard/66912.html
- OSHA — Occupational Safety and Health Administration — https://www.osha.gov
- IEEE Standards Association — standards for instrumentation and measurement systems — https://standards.ieee.org