Wire Gauge Calculator
Find the right wire gauge for amperage and distance
Breaker rating
120V or 240V
Distance from panel to load
NEC recommends max 3%
Recommended Wire Gauge
—
AWG
Actual Voltage Drop
—
%
Voltage at Load
—
V
Wire Type
—
How to Use This Calculator
Our wire gauge calculator follows NEC guidelines to recommend correct wire size.
- Identify circuit amperage
- Determine voltage
- Measure wire length
- Enter specifications
- Follow local codes
AI Insights
Smart analysis for your project
Smart Estimates
Our AI cross-references material costs, regional pricing, and project complexity for more accurate estimates.
Waste Optimization
AI-calculated waste factors based on project type, not flat percentages. Saves 5-15% on material costs.
Best Practices
Recommendations derived from building codes, contractor data, and thousands of completed projects.
Calculation Formula
Voltage drop = (2 x Length x Current x Resistance) / 1000
Minimum gauge based on NEC Table 310.16
Frequently Asked Questions
What wire gauge for 20 amp circuit?
12 AWG copper for 20 amp circuits up to 100 ft. Step up to 10 AWG for longer runs.
What happens if wire gauge is too small?
Undersized wire causes overheating, voltage drop, and fire hazard.