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Add concurrent tool demand, reserve, and compressor duty to estimate a delivered-SCFM target. Switch this compressed air calculator to convert SCFM into actual line CFM or back again using line pressure and temperature. Match the compressor's delivered rating at your required PSI; pump displacement is not usable tool air.
Estimated compressor delivery target
50.00SCFM
Planning estimate, not a compressor rating. Dry ideal air at a 14.7 psia, 60°F standard reference; gauge conversion assumes sea-level ambient pressure. Verify delivered SCFM at required PSI with the supplier. Dengaro is a financing broker and a brand of Funding Routes LLC, not the lender. No approval or rate is promised.
How it works
The air compressor sizing calculator adds three concurrent SCFM demand inputs, multiplies by one plus the reserve fraction, and divides by allowable loaded duty. Use sustained concurrent demand, not a sum of every tool owned or a tank's cubic-foot volume. A 75% compressor duty allowance means it may be loaded only three quarters of the time. The scfm to cfm calculator uses the dry ideal-gas relationship ACFM = SCFM × 14.7 ÷ (PSIG + 14.7) × (°F + 459.67) ÷ 519.67. The cfm to scfm calculator reverses it. This page defines standard air as dry air at 14.7 psia and 60°F, and assumes ambient pressure is 14.7 psia when converting gauge pressure. Other rating standards use other conditions, including 68°F. Confirm the reference on both the tool and compressor datasheets before comparing them.
Formula
Convert reserve and duty from percentages to decimals. For flow conversion use absolute pressure and absolute temperature: ACFM = SCFM × Pstandard ÷ Pactual × Tactual ÷ Tstandard. On this page Pactual = PSIG + 14.7 and Rankine temperature = Fahrenheit + 459.67. Humidity and non-ideal gas corrections are omitted.
Example
The default tool demands are 10, 15, and 5 SCFM. Their 30 SCFM total with a 25% reserve and 75% loaded-duty allowance gives 30 × 1.25 ÷ 0.75 = 50 SCFM. Separately, 100 SCFM at 90 psig and 60°F occupies 14.04 actual CFM in the compressed line. At 0 psig and 60°F, SCFM and ACFM are equal under this reference.
Tips
Check delivered SCFM at the working PSI after allowing for regulators, dryers, filters, and distribution losses. Enter all concurrent uses, including known leaks or purge demand, and avoid counting the same reserve twice. Receiver storage helps with short peaks but cannot make up a continuous air deficit. Size the tank and piping separately. Conversion here is for dry air at the specified line conditions, not automatically compressor inlet CFM.
Equipment
Ask the supplier for delivered capacity, operating duty, and the actual rating reference. Dengaro is a financing broker and a brand of Funding Routes LLC, not the lender. The equipment-financing link is for an eligible air compressor; SCFM and CFM are never passed as a loan amount. No approval or rate is promised.
Important questions
SCFM expresses air quantity at specified standard pressure and temperature. Actual CFM, or ACFM, is the volume at the measurement point's actual pressure and temperature. A compressor's advertised CFM may instead describe displacement or free-air delivery, so verify its definition before converting.
No. Reserve raises the flow target only. Your compressor must independently maintain the tools' required pressure after distribution losses. This sizing result is not a pressure-drop calculation or a horsepower selection.
It is the allowable fraction of time the compressor can run loaded, not a tool's trigger duty. Dividing by 0.75 allows a 75%-duty compressor to replenish sustained demand while spending the remaining time unloaded or off. Use the manufacturer's rating; a continuously rated machine may use 100%.
Not without a separate correction. Gauge-to-absolute conversion here assumes 14.7 psia ambient, and the formula omits water-vapor partial pressure. At altitude, for humid air, or where real-gas effects matter, use supplier calculations with local barometric pressure and the applicable standard reference.
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