Voltage Drop Calculator

Calculate voltage drop, wire size, and cable specifications for electrical circuits.

Calculation Mode

System Type

DC System AC Single Phase AC Three Phase

Current (I)

Cable Length (One Way)

Wire Gauge / CSA

Conductor Material Copper: 1.68×10⁻⁸ Ω·m | Aluminum: 2.82×10⁻⁸ Ω·m

V_drop = 2 × I × L × R

DC/Single Phase: Factor of 2 (round trip). Three Phase: Factor of √3

AWG	Diameter (mm)	Area (mm²)	Max Current (Copper)
14	1.63	2.08	15-20A
12	2.05	3.31	20-25A
10	2.59	5.26	30-40A
8	3.26	8.37	40-55A
6	4.11	13.30	55-75A
4	5.19	21.15	70-95A
2	6.54	33.62	95-130A
1/0	8.25	53.49	150-195A

Note: Current ratings vary by insulation type and installation method. NEC recommends max 3% drop for branch circuits, 5% total.