Enter the phase current into the calculator to determine the line current. For a balanced 3‑phase delta (Δ) connection, line current equals √3 times the phase (branch) current. For a balanced 3‑phase wye (Y) connection, line current equals phase current.

Line Current Calculator

Enter one value to calculate the other

Line Current Formula (Balanced Delta Connection)

The following formula is used to calculate the line current for a balanced 3‑phase delta (Δ) connection

IL = IP * SQRT(3)
  • Where IL is the line current (amps)
  • IP is the phase (branch) current in each delta leg (amps) 

For a balanced delta connection, calculate line current by multiplying the phase (branch) current by the square root of 3. For a balanced wye (Y) connection, the line current equals the phase current.

How to Calculate Line Current?

The following two example problems outline how to calculate the line current for a balanced delta (Δ) connection using the formula above.

Example Problem #1:

  1. First, determine the phase (branch) current in each delta leg (amps). In this example, the phase (branch) current is 56 A.
  2. Finally, calculate the line current using the formula above: 

IL = IP * SQRT(3)

Inserting the values from above and solving the equation with the input values gives: 

IL = 56 * SQRT(3) = 96.99 (amps)


Example Problem #2: 

Using the same process as example problem 1, we first define the variables outlined by the formula. In this case, the values are:

phase (branch) current (amps) = 82

Entering these values into the formula above gives : 

IL = 82 * SQRT(3) = 142.028 (amps)