Voltage Drop Calculator

NEC Chapter 9, Table 8 — Branch Circuit Design

Circuit Parameters

A
ft
V

Drop Threshold Gauge

Voltage Drop (%)--%
0%3%5%
Awaiting Input

Voltage Drop Analysis

Voltage Drop %
--%
Actual Drop (Vloss)
--V
Power Loss (Ploss)
--W
Recommended Next Gauge
--

NEC Reference

Single‑phase Vdrop = 2 · L · I · R1000ft / 1000
Maximum recommended drop: 3% for branch circuits (NEC 210.19 A, FPN No.4)
Resistance values from NEC Chapter 9, Table 8 (75°C)
Aluminum resistance = Copper × 1.64
Voltage Profile Along Conductor
Power Loss vs. Gauge (Relative)
Young Engineers Connect·InfraCalc