How this calculator works
The ideal-gas law equates molar flow at actual and reference states. Standard cubic feet per minute is meaningful only when reference pressure, temperature and moisture basis are stated. This tool defaults to dry gas at 15 C and 101325 Pa; other conventions can be entered. Gauge pressure is first added to the entered ambient absolute pressure. Non-ideal compressibility and water-vapour corrections are excluded. Enter flows in cubic feet per minute; converted SI volume-flow results are also shown.
Formula
Q_std = Q_actual (P_actual/P_std)(T_std/T_actual), with absolute pressures and kelvins. 1 ft3/min = 0.028316846592/60 m3/s.
Worked example
For 100 ACFM at twice the reference absolute pressure and the same temperature, standard flow is 200 SCFM. Conversely 100 SCFM becomes 50 ACFM at that pressure.
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Frequently asked questions
Which standard temperature is correct?
There is no universal SCFM reference. Use the conditions stated in the equipment specification or contract.
Can I enter gauge pressure?
Yes, choose gauge and supply the local ambient absolute pressure. A gauge reading alone cannot be used in a gas-law ratio.
Does this correct wet compressed air?
No. The same dry-gas composition and ideal-gas behaviour are assumed at both states.