Enter the phase voltage into the calculator to determine the line-to-line voltage.

Line to Line Voltage Formula

The following equation is used to calculate the Line to Line Voltage.

VL-L = SQRT(3) * PV

  • Where VL-L is the line-to-line voltage
  • PV is the phase voltage

This formula is for 3-phase systems that are equally separated by 120 degrees.

What is Line to Line Voltage?


Line to line voltage and Phase to Phase voltage are two different kinds of voltage that are found in AC circuits. In a three phase circuit, the voltage can be split in three different parts and each of these parts is called line to line voltage.

Line to line voltage is defined as the difference between two lines where the phases cross each other at right angles. Voltage is measured in volts. In a three phase system there are three lines and therefore 3 line to line voltages.

The line-to-line voltage is the voltage measured between any two phases of a 3-phase, 4 wire system. The Line to Line voltage for a 3 phase, 4 wire system is equal to the sum of all 3 wires times the phase sequence plus Neutral.