# Voltage Drop Calculator

Volts
The root-mean-square (RMS) voltage at the source of the circuit. Measured line-to-line for three-phase or line-to-neutral for single-phase circuits. Input range is from 1 to 1,000 V.
Amps
Balanced line ampacity at the load. This value is the current at maximum load. Input range is from 1 to 1,000 A.
Phase
Identical sets of parallel conductors between the source and load. All parallel conductors are assumed to be the same size.
Cos(θ)
Power factor at the load. Input range is from 0 to 1.0. 0 is purely reactive (an ideal capacitor or inductor) and 1.0 is purely resistive. Typical values for real loads are from 0.8 to 1.0.
AWG, _/0, or kcmil
Trade size of the current-carrying conductors (assumes the current is balanced). Used to look up the resistance and reactance for that specific conductor per NEC Table 9. Note: #12 aluminum resistance values assumed for #14 aluminum.
Copper or Aluminum current-carrying conductors.
Feet
One-way conductor length from source to the load. Input range is from 1 to 10,000.
Conduit material impacts conductor reactance. Choices are Steel, PVC, and Aluminum.
°C
The ambient temperature in °C. NEC Table 9 resistances are adjusted if the ambient temperature is not 75°C.
Load demand factor, an optional field. This value is used to scale the load current when calculating energy losses from the cable. Conductors are typically sized for the maximum load though average load may be less.