Shop Air Compressor Amps to Watts & Surge Sizing Calculator
Automotive garage setup, woodworker workshop electrical planning. Sizes electrical circuits and generator requirements for single-stage (120V 15A) and two-stage 240V 5HP-7.5HP stationary garage air compressors.
Step-by-Step Derivation ▼ Show Steps
Calculations adhere to standard electrical engineering physics and National Electrical Code (NFPA 70) regulations.
Engineering Principles & Calculations
This calculator uses the exact mathematical relationships between Motor Horsepower (1 HP to 10 HP), Voltage (120V / 240V), Tank Capacity (Gallons) to determine Running Amps, Running Watts, Starting Surge Amps (LRA), Minimum Generator Sizing (Watts). In practical installations, factors such as ambient raceway temperature, harmonic distortion, duty cycle continuous operation, and conductor impedance must be accounted for by a certified electrician.
Sizes electrical circuits and generator requirements for single-stage (120V 15A) and two-stage 240V 5HP-7.5HP stationary garage air compressors.
Typical Application & Industry Guidelines
Automotive garage setup, woodworker workshop electrical planning.
Shop Air Compressor Amps to Watts & Surge Sizing Calculator Benchmark Lookup Table
| Compressor HP | Running Amps @ 120V | Running Amps @ 240V | Starting Surge Amps | Min Breaker Size |
|---|---|---|---|---|
| 1.5 HP Compressor | 15.0 Amps | 7.5 Amps | 41.0 Amps | 20A (120V) / 15A (240V) |
| 2.0 HP Compressor | 19.0 Amps | 9.5 Amps | 52.0 Amps | 30A (120V) / 20A (240V) |
| 3.0 HP Shop Compressor | -- (Too large for 120V) | 14.5 Amps | 80.0 Amps | 30A 240V Breaker |
| 5.0 HP Two-Stage | -- | 24.0 Amps | 132.0 Amps | 40A or 50A 240V Breaker |