Air Compressor Calculator
The Air Compressor Calculator determines required shaft power and motor horsepower for a compressor based on free air delivery, inlet and discharge pressures, and isentropic efficiency.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Air Compressor Calculator
Compressor Power & Pressure Ratio Calculator
📐 Formula & Method
Isentropic Compression Power
Q is free air delivery in m3/s, P1 and P2 are absolute pressures in Pa, k = 1.4 for air, and eta is compressor efficiency.
Horsepower Conversion
Power is reported as shaft kW and mechanical horsepower.
📋 How to Use
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1
Enter FAD in m3/min.
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2
Enter inlet and discharge absolute pressures in bar(a).
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3
Enter isentropic/compressor efficiency.
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4
The calculator computes pressure ratio, isentropic kW, actual kW, and HP.
🧮 Worked Examples
Validation case
5 m3/min FAD, P1 = 1.013 bar(a), P2 = 7 bar(a), efficiency 75%.
Air Compressor Calculator — Engineering Reference
This calculator uses an ideal-gas isentropic compression relationship for air.
It is a preliminary estimate. Real compressor sizing needs inlet temperature, humidity, pressure losses, multi-stage/intercooling effects, FAD definition, leakage, duty cycle, and manufacturer data.
🔬 Methodology & Accuracy
Formula: Converts FAD from m3/min to m3/s, bar(a) to Pa, applies the isentropic compressor equation for air, then divides by efficiency and converts W to kW and HP.
Data sources: Ideal gas isentropic compression equation; standard air ratio of specific heats k = 1.4; 1 bar = 100,000 Pa.
Last reviewed: June 2026 · General formula used: Isentropic Compression Power · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.