Calculators
Free tools for electricians and engineers. Verify with the current NEC and a licensed pro before you install.
Single-Phase AC Voltage Drop
Calculate voltage drop on a single-phase AC circuit.
Three-Phase AC Voltage Drop
Calculate voltage drop on a three-phase AC circuit.
DC Voltage Drop
Calculate voltage drop in a DC circuit (two-conductor).
Ohm's Law Calculator
Solve for voltage, current, resistance, or power. Enter any two values.
kW / kVA to Amps
Convert kW or kVA to amps for single-phase or three-phase systems.
Conduit Fill Calculator
Check whether conductors fit in a conduit per NEC fill limits.
Wire Size Calculator
Find the minimum wire gauge that meets ampacity and voltage drop limits.
Breaker Size Calculator
Determine the minimum overcurrent protection device (OCPD) size for a given load.
Transformer kVA Sizing Calculator
Size a transformer based on secondary load current and voltage.
Motor Full-Load Amps (FLA) Calculator
Look up NEC table FLA and calculate conductor and OCPD sizing for motors.
Generator Sizing Calculator
Estimate the kW generator size needed for your load list.
Electrical Box Fill Calculator
Calculate box fill volume per NEC 314.16(B) and check against box capacity.
Equipment Grounding Conductor Size
Look up the minimum EGC size based on OCPD rating (NEC Table 250.122).
Bonding Jumper Size Calculator
Determine the minimum load-side bonding jumper size based on OCPD rating.
Power Factor Calculator
Calculate power factor and solve the power triangle (kW, kVA, kVAR).
Phase Imbalance Calculator
Calculate three-phase current imbalance percentage and check against NEMA limits.