Toolbox
Electrical calculators
Power, current, breaker and cable basics for single-phase and three-phase circuits.
Ohm's law
Solve voltage, current, resistance or power from any two.
Amps to watts
DC, single-phase and three-phase, with power factor.
kW to amps
Line current for a known load, single or three-phase.
kVA to amps
Full-load current of transformers and generators.
Three-phase power
kVA, kW and kvar from voltage, current and power factor.
Voltage drop
Volts and percent lost in a cable, with optional reactance.
NECBreaker size
Minimum breaker for continuous loads using the 125 % rule.
AWG to mm²
Wire gauge to area and diameter, and back.
NECWire size
Conductor size from load, derating and voltage drop.
NECConduit fill
Smallest EMT for a mix of conductors.
NECMotor circuit
Table full-load current, conductor, overload and device maximum.
Generator size
kW and kVA from a load list, with motor starting.
Guides