Process engineering unit converter
Pressure (gauge or absolute), temperature, flow, Nm³/h ↔ SCFM ↔ kg/h, viscosity cP ↔ cSt, energy, power, heat transfer and more — every unit an engineer uses, in one place.
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SI, US and British units, mixed freely, in every Excel tool and online tool — with a unit-converter tab built into each workbook.
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How this converter works
Every unit is converted through SI using the exact or recommended factors of NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B — for example 1 psi = 6894.757 Pa, 1 US gallon = 3.785411784 L, 1 Btu (IT) = 1055.056 J, 1 hp = 745.700 W and 1 ton of refrigeration = 3.516853 kW. Pressure can be gauge or absolute on either side, using the atmospheric pressure you enter.
Gas flow conversions use the ideal-gas molar volume at each reference condition: 22.414 Nm³/kmol at 0 °C and 1.01325 bar, 23.645 Sm³/kmol at 15 °C and 1.01325 bar, and 379.5 scf/lb-mol at 60 °F and 14.696 psia; mass flow needs the molar mass. Example: 10,000 Nm³/h of methane (16.04 kg/kmol) is 7,157 kg/h ideal-gas, or 8.96 MMSCFD. For real-gas density at line conditions, use the gas density and Z factor calculator.
Dynamic and kinematic viscosity are linked by density: cSt = cP ÷ (density in g/cm³). Enter the density to see both.