Engineering Unit Converter
Convert pressure, temperature, flow, length and mass units used in instrumentation and process engineering, and see every unit at once.
| Unit | Value |
|---|---|
| Pa | 100,000 |
| kPa | 100 |
| MPa | 0.1 |
| bar | 1 |
| mbar | 1,000 |
| psi | 14.503774 |
| atm | 0.986923 |
| kgf/cm² | 1.019716 |
| mmHg | 750.061576 |
| inHg | 29.529983 |
| mmH2O | 10,197.16213 |
| inH2O | 401.463076 |
inH2O and mmH2O use water at 4 °C; some instruments use 60 °F or 68 °F references (e.g. 1 inH2O at 60 °F ≈ 248.84 Pa). Values are absolute differences; add or subtract atmospheric pressure to convert between gauge and absolute.
Common pressure conversions
| From | Equals |
|---|---|
| 1 bar | 100 kPa = 14.504 psi = 1,000 mbar |
| 1 psi | 6.895 kPa = 68.95 mbar = 27.68 inH2O |
| 1 atm | 101.325 kPa = 1.01325 bar = 14.696 psi |
| 1 kgf/cm² | 98.0665 kPa = 0.980665 bar |
| 1 inH2O (4 °C) | 249.09 Pa = 2.491 mbar |
Gauge vs absolute pressure
Gauge pressure (barg, psig) is measured relative to atmospheric pressure; absolute pressure (bara, psia) is measured relative to a perfect vacuum. To convert, add or subtract the local atmospheric pressure (about 1.013 bar or 14.7 psi at sea level). The converter changes units only; it does not switch between gauge and absolute.
Water column references
"Inches of water" depends on the water temperature used as the reference. This tool uses 4 °C (maximum density), where 1 inH2O ≈ 249.09 Pa. Some manufacturers use 60 °F (≈ 248.84 Pa) or 68 °F (≈ 248.64 Pa). The difference is small but matters for precise DP flow and level calibrations, so check the transmitter's data sheet.
Temperature conversions
°F = °C × 9/5 + 32 K = °C + 273.15 °R = K × 9/5When converting a temperature difference (for example a 10 °C rise), do not add the offsets: a change of 1 °C equals a change of 1 K or 1.8 °F.
Flow units
The flow converter handles volumetric flow at actual conditions. Gas flows quoted at standard or normal conditions (SCFM, Nm³/h) also depend on pressure and temperature, and mass flow (kg/h) needs the fluid density.