Select a maximum voltage drop and this tool recommends the minimum copper cable size.
Current (A)
System Voltage (V)
One-way Distance
Uses round-trip length internally (2× one-way) for DC.
Units
Max Voltage Drop (%)
Continuous load safety factor
Apply ×1.25 to current
Results
Enter your numbers and click Calculate.
Warning: This tool sizes for voltage drop only. Verify ampacity based on terminations (often 60/75°C),
bundling, ambient temperature, and installation method. NEC 90°C ampacity shown is reference only.