Voltage Drop Calculator

Calculate exact voltage drop across a copper conductor run given amperage, distance, and wire gauge area.

A
ft
CM
V

Voltage Drop

4.96 V

Drop Percentage0.00 %
Voltage at Load115.0 V

Voltage Drop vs Current

सूत्र देखें →

सूत्र

## Voltage Drop Formula **Vdrop = 2 x K x I x D / CM** K is 10.8 for copper (12.9 for aluminum), I is current in amps, D is one-way distance, and CM is the wire cross-section in circular mils. The factor of 2 accounts for the round-trip path.

हल किया गया उदाहरण

20A on 12 AWG (6,530 CM) copper over 75 ft at 120V.

  1. 01Vdrop = 2 x 10.8 x 20 x 75 / 6530 = 4.96V
  2. 02Percentage = 4.96 / 120 x 100 = 4.14%
  3. 03Voltage at load = 120 - 4.96 = 115.0V
  4. 04This exceeds 3%; consider upsizing to 10 AWG.