Lighting Tool
Voltage Drop Calculator for Stage Lighting
Calculate cable voltage drop, end voltage, and drop percentage for copper or aluminium conductors in AWG or mm². Includes pass/warning/danger thresholds.
Check cable voltage drop before load-in
Enter supply voltage, current, cable length, and conductor size to see the voltage lost in the cable and the voltage arriving at the fixture.
How to use the voltage drop calculator
- Enter supply voltage and load current.
- Enter cable length and select metres or feet.
- Choose one-way or round-trip length measurement.
- Select conductor material (copper or aluminium) and gauge format.
- Read voltage drop, end voltage, and the pass/warning/danger indicator.
Notes
3% threshold
A drop above 3% is noticeable on dimmers and may affect colour on LED fixtures. Keep long runs under 3% for reliable results.
One-way vs round-trip
Current travels to the fixture and back through the return conductor. Enter the one-way length and let the tool double it, or enter the total cable run directly.
Copper vs aluminium
Aluminium has about 64% of copper's conductivity. Use a larger gauge to compensate for the higher resistivity.
AWG and mm²
AWG sizes are mapped to standard cross-sectional areas. mm² sizes follow IEC cable standards.