Standard volume70 °F
1,000SCFMEntered valueAll engineering tools
Gas flow converter
Convert standard, normal, mass and actual gas flow without losing sight of the conditions behind each value.
SCFM70 °F · 14.696 psia
Nm³/h0 °C · 1.013 bar(a)
01
Known flow value
Basis: standard volume at 70 °F and 14.696 psia. Equivalents use this value and the selected molecular weight.
02
Used for actual flowOperating conditions
Two separate operating scenarios control the two actual-flow results.
What changes what
Gas / MW→Mass ↔ volume conversion
A · Metric conditions→Actual m³/h result
B · Imperial conditions→ACFM result
Site elevation→Updates ambient pressure
03
CalculatedEquivalent flows
Basis: standard volume at 70 °F and 14.696 psia. Equivalents use this value and the selected molecular weight.
Normal volume0 °C
1,577Nm³/hMass flowMetric
2,041kg/hMass flowUS
4,500lb/hActual flow at selected conditionsIndependent conditions
A · Metric conditions1,578m³/h0 °C · 1.013 BarA · 0 BarG
B · Imperial conditions1,000ACFM70 °F · 14.696 PSIA · 0 PSIG
What do these flow terms mean?
- SCFM
- Standard volumetric flow at 70 °F and 14.696 psia.
- Nm³/h
- Normal volumetric flow at 0 °C and 1.013 bar(a).
- m³/h · A
- Volume occupied per hour at the metric temperature and pressure in condition set A.
- ACFM · B
- Volume occupied per minute at the imperial temperature and pressure in condition set B.
- Mass flow
- Mass passing through the system per unit of time; it does not change when only pressure or temperature changes.
Preliminary calculation only
Results assume ideal-gas behaviour (Z = 1), the selected molecular weight and the displayed reference and operating conditions. Actual composition, compressibility and moisture may affect the result. Do not use this tool as the sole basis for valve selection, equipment sizing or safety-related calculations.
Understanding gas flow conversion
A gas does not occupy a fixed volume. Its volumetric flow changes with pressure and temperature, even when the amount of gas and the mass flow remain unchanged. A useful conversion must therefore identify both the flow unit and the conditions attached to it.
Ideal-gas basis
This converter uses the ideal-gas relationship as a preliminary calculation basis. Pressure, volume and absolute temperature are related through PV = nRT. Molecular weight then connects molar flow with mass flow. The calculation assumes a compressibility factor Z of 1; real gases may require a corrected equation of state.
Standard, normal and actual flow
SCFM and Nm³/h express gas volume at defined reference conditions, making flows easier to compare. Actual m³/h and ACFM describe the volume occupied at the selected operating pressure and temperature. Actual values can therefore change substantially while standard flow and mass flow remain the same.
Why molecular weight matters
Converting between volumetric and mass flow requires the density of the gas. Under the ideal-gas assumption, density depends on pressure, temperature and molecular weight. For a gas mixture, use the molecular weight of the complete mixture rather than that of a single component.
How to use the result
Use the converter for preliminary comparison, unit normalization and preparation of process data. Confirm gas composition, compressibility, moisture, reference conditions and project requirements before using a result for valve selection, line sizing, equipment sizing or any safety-related decision.
SCFM: Standard cubic feet per minute at 70 °F and 14.696 psia.
Nm³/h: Normal cubic metres per hour at 0 °C and 1.013 bar(a).
Actual m³/h / ACFM: Volume flowing at the pressure and temperature of the operating scenario.
kg/h / lb/h: Mass passing through the system per unit of time, expressed here in kg/h or lb/h.