Voltage Drop Calculator

Calculate voltage drop and percentage loss for electrical circuits. Supports Copper/Aluminum wires and various gauges.

Wire & Specifics

Wire Material

Wire Size (AWG)

Voltage (V)

Current (Amps)

One-Way Distance (Feet)

Circuit Type

Voltage Drop Analysis

Voltage Drop

3.96 Volts

(3.30%)

Warning: Drop exceeds NEC recommended 3% limit.

Voltage at End

116.04 V

Calculations based on NEC Chapter 9, Table 8 DC resistance values at 75°C. Actual drop may vary with temperature and conduit type.

About Voltage Drop

Why It Matters

Voltage drop creates heat, wastes energy, and can prevent equipment from running correctly. The National Electrical Code (NEC) recommends a maximum voltage drop of 3% for branch circuits to ensure efficiency.

Factors Affecting Drop

Wire Gauge: Thinner wires (higher AWG numbers) satisfy more resistance, causing more drop.
Distance: Longer runs increase total resistance.
Material: Aluminum has higher resistance than copper for the same thickness.
Current: Higher amps cause more drop (Ohm's Law: V = I × R).