Compressor CFM to HP Converter #

Convert between standard compressor flow and package input-power equivalent using a specific-power value from a matching OEM performance point or a verified measurement. For demand and pressure sizing, use the air compressor sizing calculator.

Quick Calculator: Conversion Parameters

Convert

Standard Flow (SCFM @ stated rating condition)

Package Specific Power (kW/100 SCFM)Use OEM or measured package input power and FAD at matching pressure and reference conditions

Advanced calculator: Annual Scenario

These inputs affect only the annual energy and cost scenario.

Operating Hours per Year

Average Input-Power Load Factor (%)

Energy Rate ($/kWh)

About this calculator

This converter does not infer compressor performance from type or apply a generic pressure correction. It uses only the entered package specific power, which must match the flow reference condition, discharge pressure, cooling/package boundary, and operating point. “HP equivalent” is kW divided by 0.745699872; it is not an automatic motor-nameplate recommendation. Worked example: 100 SCFM at 20 kW/100 SCFM corresponds to 20.0 kW or 26.82 input HP equivalent. At 4000 hours, 70% load factor, and $0.12/kWh, the scenario is 56,000 kWh and $6,720 per year. Browse all pneumatic calculators.

Result

Converted Value

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Entered Specific Power

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Package Input and Annual Energy

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Annual Energy-Cost Scenario

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Continue Your Calculation

After CFM/HP conversion, run full compressor sizing for total plant demand and receiver tank reserve.

Size compressor →

Quick Reference #

Common values and conversions for quick reference. Use these as starting points for your calculations.

Parameter	Imperial	Metric	Notes
Standard Pressure	14.7 PSIA	1.013 bar	Atmospheric at sea level
Standard Temp	60F (520R)	15.6C (288.7K)	SCFM reference
CFM to L/s	1 CFM	0.4719 L/s	Flow rate conversion
PSI to bar	1 PSI	0.06895 bar	Pressure conversion
HP to kW	1 HP	0.7457 kW	Power conversion

Formulas and Method #

Specific-Power Conversion

Input kW = SCFM × (kW / 100 SCFM) ÷ 100; input HP equivalent = input kW ÷ 0.745699872

The reverse conversion divides input kW by the matching specific power. It is valid only when the entered flow and package power share the same rating conditions and system boundary.

Assumptions and Limitations

The tool does not predict FAD, correct performance for pressure, or determine motor nameplate HP. Package input must include the boundary used by the source data. Part-load performance is not generally linear; the annual scenario is valid only when its entered average input-power load factor represents the operating profile.

Source-Data Checklist #

Before entering specific power, confirm the source identifies FAD/standard-flow reference conditions, discharge pressure, inlet conditions, package power boundary, cooling auxiliaries, operating point, and test method. Do not combine flow from one rating point with power from another.

Frequently Asked Questions #

How many CFM per HP does an air compressor produce?

There is no reliable universal value by compressor type or motor HP. Use the candidate package’s FAD and input kW at the required pressure and matching reference conditions, then calculate specific power. Motor nameplate HP alone does not establish delivered flow.

Does higher pressure reduce compressor CFM?

Changing discharge pressure changes package flow and input power, but the relationship is machine- and control-specific. Use the manufacturer performance curve or measured data at the required pressure rather than a fixed percentage correction.

What is the difference between SCFM and ACFM?

SCFM is volume flow referred to stated standard pressure and temperature; ACFM is volume flow at actual line conditions. Always state the reference condition. This converter uses the entered standard-flow performance point and does not convert to ACFM.