Electrical Wire Gauge & Voltage Drop Calculator
Calculate recommended AWG wire gauge (14, 12, 10, 8, 6, 4) and verify voltage drop is under the 3% NEC limit for 120V/240V circuits.
Input Parameters
Enter dimensions and specifications to estimate materials.
Recommended Wire Gauge (AWG)
Calculated Voltage Drop
2.29V (1.91%)
Circuit Breaker Size
20Amps
One-Way Distance
75ft
NEC Drop Compliance
Compliant (<3%)
Material estimates include recommended trade waste buffer. Always confirm dimensions on site prior to ordering.
How The Calculation Works
Formulas, material coverage assumptions, waste buffers, and rounding standards.
National Electrical Code (NEC) specifies wire ampacity thresholds (14 AWG for 15A, 12 AWG for 20A, 10 AWG for 30A, 8 AWG for 40A, 6 AWG for 55A).
Over long distances, wire resistance causes voltage drop; if the voltage drop exceeds 3%, the wire gauge must be upsized to the next thicker conductor.
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Frequently Asked Questions
Practical installation guidance and purchasing tips for electrical wire gauge & voltage drop calculator.