Voltage Drop Calculator

Calculate voltage drop in electrical cables and conductors. Determine if your wire size is adequate and calculate power losses in electrical circuits.

About Voltage Drop

Voltage drop is the reduction in voltage that occurs when current flows through a conductor's resistance. Excessive voltage drop can cause equipment malfunction and energy waste.

NEC Requirements:

  • Branch Circuits: Maximum 3% voltage drop
  • Feeders: Maximum 3% voltage drop
  • Combined: Maximum 5% total voltage drop

Effects of Excessive Voltage Drop:

  • Reduced equipment performance
  • Increased energy consumption
  • Shortened equipment life
  • Potential safety hazards