Pounds-force per square inch to Bar Calculator

Direct answer

Multiply the entered pounds-force per square inch value by 0.06894757293 to express it in bar (bar). This converts pound-force per square inch (psi) to bar (bar) within the documented pressure family.

Variables and formula

• Pounds-force per square inch (psi): the source value measured in pound-force per square inch.
• Bar (bar): the same quantity expressed in bar.
• Conversion factor: 0.06894757293 bar per pound-force per square inch.

Bar = Pounds-force per square inch × 0.06894757293

The generator emits numeric factors with at most 15 significant digits. Calculator results keep up to 10 significant digits for display; this formatting does not increase the precision of the measurement.

Unit definitions and named variants

Source unit: pound-force per square inch (psi). Psi in this family is pound-force per square international inch (lbf/in²). With standard gravity it is approximately 6894.75729316836 Pa. Named variant used: Pound-force per square inch using standard gravity; not pound-mass per square inch. Gauge versus absolute reference must be specified separately. Reference: National Institute of Standards and Technology: NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically; National Institute of Standards and Technology: NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement.

Target unit: bar (bar). The bar is a non-SI pressure unit defined as 0.1 MPa or exactly 100,000 Pa. Named variant used: Pressure unit bar; not the unrelated typographic or musical word. Reference: Bureau International des Poids et Mesures: The International System of Units (SI), 9th edition, version 4.01; National Institute of Standards and Technology: NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically.

The psi-to-bar direction remains inside the pressure quantity; it changes the unit label and numerical scale, not the kind of quantity being measured.

Relationship and precision

This route uses at least one deliberately preserved rounded factor. Treat the displayed factor as an approximation at the precision documented below.

• psi relationship: The preserved baseFactor 6894.757293 Pa is rounded from about 6894.75729316836 Pa, a difference of about 1.68×10⁻⁷ Pa per psi.
• bar relationship: The relationship to the pascal is exact.

To audit the factor through the family base unit, divide the raw dataset factors 6894.757293 by 100000. The generator emits that quotient once at 15 significant digits as the canonical direct factor 0.06894757293; runtime calculations do not divide the already-emitted base factors again.

Reproducible example

For 10 pounds-force per square inch, 10 × 0.06894757293 = 0.6894757293 bar. Repeating the same multiplication with the stated factor reproduces the displayed conversion before interface rounding.

Directional scale check

Because one pound-force per square inch contains 0.06894757293 bar, the target number is smaller than the source number for every positive input. Zero maps to zero, while negative inputs are rejected because this family models non-negative magnitudes.

Interpretation

Read the result as bar, not pounds-force per square inch. A value entered as psi leaves the calculator labelled bar; this directional distinction matters even when the two units describe the same pressure quantity.

Assumptions and limitations

• Only non-negative pressure magnitudes are accepted; negative gauge readings require a signed, reference-aware model.
• This family converts non-negative pressure magnitudes only. It does not add or subtract atmospheric reference pressure when changing between absolute, gauge, differential, or vacuum readings.
• Input and output must refer to the same pressure reference and measurement conditions; a unit conversion alone cannot change the reference datum.

Common mistakes

• psig and psia share the same unit size but use different zero references; conversion between them requires ambient/reference pressure.
• One bar is not exactly one standard atmosphere; 1 atm = 1.01325 bar.

Continue within the Pressure family

See the Pressure conversion hub for its five-unit reference table and all 20 directed routes.

• Reverse the direction: Bar to Pounds-force per square inch
• Compare another pressure route: Pounds-force per square inch to Pascals
• Compare another pressure route: Pounds-force per square inch to Kilopascals
• Compare another pressure route: Pounds-force per square inch to Standard atmospheres
• Compare another pressure route: Bar to Pascals

Assumptions

• The entered value uses pounds-force per square inch exactly as labelled.
• Only non-negative pressure magnitudes are accepted; negative gauge readings require a signed, reference-aware model.
• Rounding and measurement uncertainty remain the user's responsibility.

Sources and methodology

CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.

• The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; accessed Aug 7, 2026
• NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically; National Institute of Standards and Technology; accessed Aug 7, 2026
• NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement; National Institute of Standards and Technology; accessed Aug 7, 2026