How this calculator works
Enter current (a), one-way length (m), wire resistance (ω/m), supply voltage (v). CalcStack applies the displayed formula and reports each intermediate planning value with the units shown.
Formula / method
Voltage drop = 2 × length × current × resistance per meter
Worked example
20 A over 30 m with 0.00172 Ω/m wire drops about 2.064 V on a 120 V supply.
Assumptions and limitations
Conductors have equal outbound and return length at stable temperature.
Connections, AC impedance, temperature, bundling and code requirements are excluded.