Voltage Drop Calculator

Optimize your low-voltage LED landscape lighting design with our easy-to-use Voltage Drop Calculator.

Calculate amperage draw, line loss, and voltage at the first and last fixture across 8 to 22 AWG wire runs. Ensure your low voltage outdoor lighting installation stays within safe operating limits and prevents unwanted dimming or flickering.

Voltage Drop Calculator
Total Amperage Load: 0.00 A
First Fixture
Drop to 1st Fixture: 0.00 V
Voltage at 1st Fixture: 0.00 V
End of Run
Total Voltage Drop: 0.00 V
Voltage at Last Fixture: 0.00 V
Total Percentage Loss: 0.00%
Voltage drop within 10% limit
System Optimization Suggestions

  • Understanding Voltage Drop in Outdoor Lighting

    When electricity travels through a landscape wire, it loses a small amount of power along the way—this loss is called voltage drop. If the voltage drops too low, lights at the end of a long wire run may flicker, dim, or fail to turn on.

    What is the ideal voltage range?

    Modern low-voltage LED landscape lights require 10.8 volts to 15.0 volts to operate properly:

    • Ideal Target (11V to 12V): For maximum performance and bulb life, every light on the run should receive around 11 to 12 volts. Always check the product specifications - some low voltage fixtures run natively at 15V outputs.
    • Maximum Recommended Loss (10% Drop): On a standard 12-volt output, a voltage loss of 10% or less keeps your furthest light above the required 10.8-volt floor.
    • Too Low (< 10.8V): Lights may flicker, shut off, or change color.
    • Too High (> 15.0V): Over-supplying voltage overheats internal LED drivers and shortens the lifespan of the fixture.

  • How to fix excessive voltage drop:

    If your calculation shows too much loss:

    1. Use thicker wire (upgrade from 12 AWG to 10 AWG wire).
    2. Connect to a higher output tap on a multi-tap transformer (such as 13V or 14V).
    3. Split your lights into smaller wire runs or connect the wire to the middle of the lighting run rather than the beginning.