Electricians
Wire Gauge Calculator
Find the correct AWG wire gauge for any amperage load based on NEC ampacity tables.
Based on NEC Table 310.16. Always use the next larger standard wire size when your exact amperage falls between table values. Apply correction factors for conduit fill, ambient temperature above 86°F, or long runs. Aluminum wiring requires special connectors and is not approved for all applications - consult local code.
Common Questions
What wire gauge do I need for a 20 amp breaker?
A 20 amp circuit needs 12 AWG copper wire minimum per NEC Table 310.16. Never use 14 AWG on a 20 amp breaker.
What wire size do I need for a 30 amp circuit?
A 30 amp circuit requires 10 AWG copper wire. Common uses include electric dryers and some air conditioner units.
What wire gauge do I need for a 50 amp circuit?
A 50 amp circuit needs 6 AWG copper wire. Common uses include electric ranges and EV chargers.
When should I use aluminum wire instead of copper?
Aluminum wire is common for service entrances and large feeder runs because it costs less than copper at larger sizes. It is not recommended for branch circuits. Always use connectors rated for aluminum and follow NEC Article 310.
What does AWG stand for?
AWG stands for American Wire Gauge. The smaller the AWG number, the thicker the wire and the more current it can carry. 4 AWG is thicker than 12 AWG.
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