Pressure conversion table: bar, psi, kPa, kgf/cm², mH₂O and mmHg
Conversion factors between bar, mbar, kPa, MPa, psi, kgf/cm², atm, mH₂O and mmHg (NIST SP 811), and common bar values in psi, kPa, kgf/cm² and mH₂O.
Each row gives the value of 1 unit in the others. The factors come from the unit definitions (NIST SP 811): 1 psi is one pound-force per square inch, 1 kgf/cm² uses standard gravity and the liquid columns are conventional.
| 1 unit = | bar | mbar | kPa | MPa | psi | kgf/cm² | atm | mH₂O | mmHg |
|---|---|---|---|---|---|---|---|---|---|
| 1 bar | 1 | 1000 | 100 | 0.1 | 14.5038 | 1.01972 | 0.986923 | 10.1972 | 750.062 |
| 1 mbar | 0.001 | 1 | 0.1 | 0.0001 | 0.0145038 | 0.00101972 | 0.000986923 | 0.0101972 | 0.750062 |
| 1 kPa | 0.01 | 10 | 1 | 0.001 | 0.145038 | 0.0101972 | 0.00986923 | 0.101972 | 7.50062 |
| 1 MPa | 10 | 10000 | 1000 | 1 | 145.038 | 10.1972 | 9.86923 | 101.972 | 7500.62 |
| 1 psi | 0.0689476 | 68.9476 | 6.89476 | 0.00689476 | 1 | 0.070307 | 0.068046 | 0.70307 | 51.7149 |
| 1 kgf/cm² | 0.980665 | 980.665 | 98.0665 | 0.0980665 | 14.2233 | 1 | 0.967841 | 10 | 735.559 |
| 1 atm | 1.01325 | 1013.25 | 101.325 | 0.101325 | 14.6959 | 1.03323 | 1 | 10.3323 | 760 |
| 1 mH₂O | 0.0980665 | 98.0665 | 9.80665 | 0.00980665 | 1.42233 | 0.1 | 0.0967841 | 1 | 73.5559 |
| 1 mmHg | 0.00133322 | 1.33322 | 0.133322 | 0.000133322 | 0.0193368 | 0.00135951 | 0.00131579 | 0.0135951 | 1 |
| bar | psi | kPa | kgf/cm² | mH₂O |
|---|---|---|---|---|
| 0.5 | 7.2519 | 50 | 0.50986 | 5.0986 |
| 1 | 14.504 | 100 | 1.0197 | 10.197 |
| 2 | 29.008 | 200 | 2.0394 | 20.394 |
| 3 | 43.511 | 300 | 3.0591 | 30.591 |
| 4 | 58.015 | 400 | 4.0789 | 40.789 |
| 5 | 72.519 | 500 | 5.0986 | 50.986 |
| 6 | 87.023 | 600 | 6.1183 | 61.183 |
| 8 | 116.03 | 800 | 8.1577 | 81.577 |
| 10 | 145.04 | 1000 | 10.197 | 101.97 |
| 16 | 232.06 | 1600 | 16.315 | 163.15 |
| 20 | 290.08 | 2000 | 20.394 | 203.94 |
| 25 | 362.59 | 2500 | 25.493 | 254.93 |
| 40 | 580.15 | 4000 | 40.789 | 407.89 |
| 100 | 1450.4 | 10000 | 101.97 | 1019.7 |
Watch out for
- Gauge and absolute: the conversion is the same for both, but do not mix them. 1 bar gauge is about 2 bar absolute at sea level.
- mH₂O (metre of water column) uses water at 1000 kg/m³; mmHg uses conventional mercury; both with standard gravity (9.80665 m/s²).
- kgf/cm² is practically the technical atmosphere (at), slightly less than 1 atm.
Values calculated from the reference functions; they do not replace measurement or a calibration certificate.