Wire Size Calculator (AWG)
Calculate the minimum wire gauge (AWG) for your electrical circuit based on amperage, voltage, distance, and conductor material. NEC compliant electrical wire sizing calculator for safe installations.
Why Use Our Wire Size Calculator?
NEC Code Compliant
Calculations follow National Electrical Code standards for safe wire sizing and voltage drop limits
Multiple Circuit Types
Supports single-phase, three-phase, and DC circuits with copper or aluminum conductors
Voltage Drop Analysis
Calculates voltage drop percentage to ensure proper circuit performance
Common Wire Size Reference Guide
12 AWG
20 Amp Circuit
Outlets, lighting, small appliances
10 AWG
30 Amp Circuit
Electric dryers, water heaters
6 AWG
50 Amp Circuit
Electric ranges, large appliances
These are typical residential applications. Actual wire size depends on specific circuit requirements, distance, and local electrical codes.
Calculate Wire Size (AWG)
Enter your circuit specifications to determine the minimum required wire gauge
Enter the maximum current the circuit will carry
Distance from panel to load (one-way)
Ampacities shown for copper wire at 75°C. Aluminum wire has lower capacity.
AWG Wire Size Chart
Reference chart showing AWG wire sizes, current capacity, and typical applications for electrical installations.
Copper Wire (75°C)
Aluminum Wire (75°C)
Wire Size by Application
Wire sizes shown are for typical applications. Always consult local electrical codes and consider specific installation conditions.
Wire Size Calculator FAQ
How do I calculate wire size for my circuit?
Wire size depends on three main factors: current load (amps), circuit distance, and voltage drop requirements. Our calculator considers NEC ampacity tables and calculates voltage drop to recommend the minimum safe wire size. Always size wire to handle 125% of the continuous load.
What's the difference between copper and aluminum wire sizing?
Aluminum wire has higher resistance than copper, so it requires a larger gauge (smaller AWG number) for the same current capacity. For example, while 12 AWG copper handles 20 amps, you need 10 AWG aluminum for the same load. Aluminum is less expensive but requires special connectors and installation techniques.
Why does distance affect wire size?
Voltage drop increases with distance due to wire resistance. The NEC recommends keeping voltage drop under 3% for branch circuits and 5% total. Longer runs require larger wire to maintain proper voltage at the load. Our calculator automatically accounts for distance-based voltage drop.
When should I size up from the calculated wire size?
Consider larger wire for: Future expansion (easy to install larger wire now), long runs (reduces voltage drop), high-demand circuits (reduces heating), motor loads (high starting current), and locations with poor ventilation (heat buildup concerns). Going one size larger is often worth the small extra cost.
Important Safety Notice
This calculator provides estimates based on NEC guidelines. Always consult local electrical codes and have electrical work performed by qualified electricians. Improper wire sizing can cause fires, equipment damage, or electrocution. When in doubt, consult a licensed professional.
Need Professional Electrical Work?
Connect with qualified electricians for safe wire installation, electrical upgrades, and code-compliant electrical work.