Conversion method
Unit conversion does not change the pressure reference: gauge and absolute pressure are different measurements. A bar is exactly 100,000 Pa; standard atmosphere is 101,325 Pa. Mercury-based values use conventional constants.
bar = x × 0.0689475729316836
10 psi = 0.689476 bar.
| psi | bar |
|---|---|
| 1 | 0.068948 |
| 5 | 0.344738 |
| 10 | 0.689476 |
| 25 | 1.723689 |
| 50 | 3.447379 |
| 100 | 6.894757 |
Unit definitions and sources
Keep gauge and absolute pressure references consistent. Mercury-column values depend on their conventional reference conditions.
25 of the 36 definitions below were checked against the cited sources on 2026-09-20 (AI-assisted check).
| Unit and system | Use | Definition | Relationship |
|---|---|---|---|
| Pascal (Pa); si | Common units | Pascal measures pressure. pa = (value in Pa) × 1. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Kilopascal (kPa); si | Common units | Kilopascal measures pressure. pa = (value in kPa) × 1000. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Megapascal (MPa); si | Common units | Megapascal measures pressure. pa = (value in MPa) × 1000000. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Bar (bar); metric | Common units | Bar measures pressure. pa = (value in bar) × 100000. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Millibar (mbar); metric | Common units | Millibar measures pressure. pa = (value in mbar) × 100. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Pound per square inch (psi); us | Common units | Pound per square inch measures pressure. pa = (value in psi) × 6894.757293168361. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Standard atmosphere (atm); other | Common units | Standard atmosphere measures pressure. pa = (value in atm) × 101325. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Millimeter of mercury (mmHg); other | Common units | Millimeter of mercury measures pressure. pa = (value in mmHg) × 133.322387415. Common use: Pressure readings with a consistent reference. | Approximate / conventional |
| Kilopound per square inch (ksi); us | Specialist units | Kilopound per square inch measures pressure. pa = (value in ksi) × 6894757.293168361. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Torr (Torr); other | Specialist units | Torr measures pressure. pa = (value in Torr) × 133.32236842105263. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Inch of mercury (inHg); us | Specialist units | Inch of mercury measures pressure. pa = (value in inHg) × 3386.389. Common use: Pressure readings with a consistent reference. | Approximate / conventional |
| Exapascal (EPa); si | Specialist units | exapascal: E denotes 10^18; the unit gives 1000000000000000000 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Petapascal (PPa); si | Specialist units | petapascal: P denotes 10^15; the unit gives 1000000000000000 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Terapascal (TPa); si | Specialist units | terapascal: T denotes 10^12; the unit gives 1000000000000 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Gigapascal (GPa); si | Specialist units | gigapascal: G denotes 10^9; the unit gives 1000000000 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Hectopascal (hPa); si | Specialist units | hectopascal: h denotes 10^2; the unit gives 100 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Decapascal (daPa); si | Specialist units | decapascal: da denotes 10^1; the unit gives 10 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Decipascal (dPa); si | Specialist units | decipascal: d denotes 10^-1; the unit gives 0.1 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Centipascal (cPa); si | Specialist units | centipascal: c denotes 10^-2; the unit gives 0.01 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Millipascal (mPa); si | Specialist units | millipascal: m denotes 10^-3; the unit gives 0.001 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Micropascal (µPa); si | Specialist units | micropascal: µ denotes 10^-6; the unit gives 0.000001 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Nanopascal (nPa); si | Specialist units | nanopascal: n denotes 10^-9; the unit gives 1e-9 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Picopascal (pPa); si | Specialist units | picopascal: p denotes 10^-12; the unit gives 1e-12 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Femtopascal (fPa); si | Specialist units | femtopascal: f denotes 10^-15; the unit gives 1e-15 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Attopascal (aPa); si | Specialist units | attopascal: a denotes 10^-18; the unit gives 1e-18 pa. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Newton/square meter (N/(m²)); other | Specialist units | newton/square meter = 1.0 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Newton/square centimeter (N/(cm²)); other | Specialist units | newton/square centimeter = 10000.0 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Newton/square millimeter (N/(mm²)); other | Specialist units | newton/square millimeter = 1000000.0 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Kilonewton/square meter (kN/(m²)); other | Specialist units | kilonewton/square meter = 1000.0 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Dyne/square centimeter (dyn/(cm²)); other | Specialist units | dyne/square centimeter = 0.1 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Kilogram-force/square meter (kgf/(m²)); other | Specialist units | kilogram-force/square meter = 9.80665 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Kilogram-force/sq. cm (kgf/(cm²)); other | Specialist units | kilogram-force/sq. cm = 98066.5 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Kilogram-force/sq. millimeter (kgf/(mm²)); other | Specialist units | kilogram-force/sq. millimeter = 9806650.0 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Gram-force/sq. centimeter (gf/(cm²)); other | Specialist units | gram-force/sq. centimeter = 98.0665 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Pound-force/square foot (lbf/(ft²)); other | Specialist units | pound-force/square foot = 47.88025898033584 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
| Pound-force/square inch (lbf/(in²)); other | Specialist units | pound-force/square inch = 6894.757293168361 pa, derived from the component SI/customary definitions. Common use: Pressure readings with a consistent reference. | Exact definition; numerical display may be rounded |
Sources: BIPM: International System of Units; NIST: SP 811 Appendix B.8: conversion factors; BIPM: SI prefixes
Precision of pressure conversions
All 36 pressure units convert through Pascal (Pa). 34 have an exact defined relationship to the base unit and 2 are conventional or measured values. Results and the tables on this page come from the same engine, so a table value can be checked against the converter directly.
Standard display shows up to six decimal places, switching to scientific notation for very large or small values. Calculation uses JavaScript binary floating point independently of display rounding, so extra digits are not a claim about measurement accuracy. Each unit lists its own source; a citation records where the definition comes from, not an independent review. See Conversion methodology for the review and correction process.