← TOOL INDEX / WT-077
WT-077 V↓
HOME / CONSTRUCTION / LOCAL UTILITY

Voltage Drop Calculator

Estimate conductor voltage drop, percentage loss, load voltage, resistance, and wire power loss for common AWG copper or aluminum conductors.

ELECTRICAL
LOCAL NO DATA SENT
VOLTAGE DROP CALCULATORAWG / COPPER / ALUMINUM / 1Φ / 3Φ
CIRCUITENTER A PLANNING SCENARIO
Uses a simplified conductor-resistance estimate based on circular mil area and common K factors. Real AC circuits can differ because of temperature, impedance, power factor, installation method, and conductor construction.
VOLTAGE DROP
LOAD VOLTAGE
CIRCUIT RESISTANCE
POWER LOSS
CIRCULAR MILS
HOW IT WORKSSHOW THE ESTIMATE
READYEnter circuit values to estimate voltage drop.

PLANNING TOOL: Inputs stay in your browser. This calculator is an estimate, not an electrical design or code-compliance determination. Conductor ampacity, overcurrent protection, temperature correction, conduit fill, local code, equipment instructions, and other requirements must be checked separately by a qualified person.

FIELD NOTE / 077

Voltage drop increases with current and wire length and decreases as conductor area increases.

For a simplified DC or single-phase estimate, voltage drop is approximately 2 × K × current × one-way length ÷ circular mil area. Three-phase calculations use √3 instead of 2. The calculator shows the estimated drop, percentage, load voltage, resistance, and wire loss.