ICFM to SCFM Converter
ICFM (Inlet Cubic Feet per Minute) refers to the gas volumetric flow measured at the compressor inlet flange conditions. It is essentially the same concept as ACFM but specifically...
Formula
Source: Engineering Toolbox, CAGI standards | Last reviewed: June 7, 2026
Examples
100 ICFM
= 100 SCFM
- T_actual = 70
- P_atm_psi = 14.7
At standard inlet conditions, ICFM = SCFM
100 ICFM
= 95.7 SCFM
- T_actual = 90
- P_atm_psi = 14.5
Warm inlet with filter pressure drop
100 ICFM
= 81.5 SCFM
- T_actual = 32
- P_atm_psi = 12.2
Cold inlet at high altitude (5000 ft)
Where is this used?
A compressor's ICFM rating accounts for the actual inlet conditions (filter drop, ambient temperature, elevation).
Converting to SCFM allows comparison with standard compressor data sheets and helps size intake filters and ductwork.
Frequently Asked Questions
What is the difference between ICFM and ACFM?
ICFM is specifically the flow at the compressor inlet flange. ACFM is a more general term for actual flow at any point. In practice, they are calculated the same way using the ideal gas law.
How does inlet filter condition affect ICFM?
A clogged inlet filter creates a vacuum at the compressor inlet, lowering P_atm_psi. This increases the ICFM for the same mass flow. A 2 psi filter drop at sea level changes ICFM by about 14%.
Which standard does this use?
This converter uses CAGI/ISO standard conditions: 68°F (520°R) and 14.696 psia. Always verify which standard your equipment manufacturer uses.
Reviewed for accuracy
· Last reviewed: June 7, 2026
All calculations are for reference only. Always verify with manufacturer data and a qualified engineer for critical applications. Learn about our editorial process.