Wire Gauge Chart: AWG Sizes and Amps
Wire gauge numbers run backwards: a bigger AWG number means a thinner wire. This chart lists every common size from 14 to 4/0 AWG with its circular mil area and ampacity, then shows when a long run forces you to pick a bigger size than the amp chart alone suggests.
This wire gauge chart covers 14 AWG through 4/0 AWG with circular mil area and NEC 310.16 ampacity at 60, 75, and 90 degrees C for copper. Bigger AWG numbers mean thinner wire, and long runs often force a larger size than the amp rating alone, because voltage drop, not ampacity, becomes the limit.
AWG numbers run backwards
AWG stands for American Wire Gauge. The scale is counterintuitive: 14 AWG is thin, 4/0 AWG is thick. The number originally counted how many times the wire was drawn through a die, so more draws meant a thinner wire and a bigger number. When someone says "go up a size," they usually mean a thicker wire, which is a smaller AWG number: from 12 AWG up to 10 AWG, for example.
The full AWG chart: circular mils and ampacity
Ampacity values below come from NEC Table 310.16 for copper conductors, three current-carrying wires in a raceway at 30 degrees C ambient. The three columns are the 60, 75, and 90 degree C temperature ratings. Circular mils (CM) are the wire's cross-sectional area, the number the voltage drop formula uses.
14 AWG: 4,110 CM; 15 / 20 / 25 amps
12 AWG: 6,530 CM; 20 / 25 / 30 amps
10 AWG: 10,380 CM; 30 / 35 / 40 amps
8 AWG: 16,510 CM; 40 / 50 / 55 amps
6 AWG: 26,240 CM; 55 / 65 / 75 amps
4 AWG: 41,740 CM; 70 / 85 / 95 amps
3 AWG: 52,620 CM; 85 / 100 / 115 amps
2 AWG: 66,360 CM; 95 / 115 / 130 amps
1 AWG: 83,690 CM; 110 / 130 / 145 amps
1/0 AWG: 105,600 CM; 125 / 150 / 170 amps
2/0 AWG: 133,100 CM; 145 / 175 / 195 amps
3/0 AWG: 167,800 CM; 165 / 200 / 225 amps
4/0 AWG: 211,600 CM; 195 / 230 / 260 amps
Two hard limits sit on top of this chart. NEC 240.4(D) caps the breaker at 15 amps for 14 AWG, 20 amps for 12 AWG, and 30 amps for 10 AWG in most residential work, regardless of what the 75 or 90 degree columns say. And aluminum needs larger sizes for the same current: 12 AWG aluminum is 20 amps at 75 degrees, 10 AWG is 30, 8 AWG is 40, 6 AWG is 50, 4 AWG is 65, 2 AWG is 90, 1/0 is 120, and 4/0 is 180.
Reading the temperature columns
The 60 degree column is the default for NM-B (Romex) cable and for most residential terminations. The 75 degree column applies when both the wire insulation and the breaker terminals are rated 75 degrees, which covers most modern panelboards. The 90 degree column is almost never your final answer; it is used for derating math when wires are bundled or ambient temperature is high, then the result is still capped by the termination rating.
Why the chart is only half the answer: distance
Ampacity tells you the wire will not overheat. It says nothing about how much voltage arrives at the load. Take a 120 volt, 15 amp circuit with a 100 foot one-way run on 12 AWG copper. The amp chart says 12 AWG is fine for 15 amps. But the voltage drop formula (VD = 2 x 12.9 x 15 x 100 / 6530) gives 5.93 volts, or 4.94 percent, well past the NEC 3 percent branch-circuit guidance.
Upsize to 10 AWG and the drop falls to 3.73 volts, or 3.11 percent: closer, but still over. Upsize again to 8 AWG and you land at 2.34 volts, or 1.95 percent, comfortably inside the guidance. Same current, same distance, three different answers from the amp chart alone versus the drop calculation. This is why long runs to sheds, wells, barns, and detached garages almost always need a bigger wire than the breaker size suggests.
Copper vs aluminum on the chart
Aluminum has higher resistance, so it needs roughly two sizes larger than copper for the same job: where 3 AWG copper carries 100 amps at 75 degrees, aluminum needs 1 AWG. Aluminum is economical for large feeders, but it demands compatible terminals, anti-oxidant compound at terminations, and careful torque. Never mix copper and aluminum under the same lug unless the device is listed for it.
A note on safety: wire sizing involves the National Electrical Code, breaker rules, and local amendments. The examples below are planning estimates. Have a licensed electrician review any real installation before you buy wire or pull a permit.
Skip the arithmetic
Planning a long run? Enter your voltage, distance, current, and wire gauge to see the exact drop in volts and percent, or work backwards to the smallest size that meets your target.
Wire gauge chart questions
What does AWG stand for?
AWG stands for American Wire Gauge, the standard system for sizing round electrical conductors in North America. The scale runs backwards: a larger AWG number means a thinner wire, so 14 AWG is thinner than 10 AWG.
Is 12 gauge thicker than 14 gauge?
Yes. Because AWG numbers run backwards, 12 AWG (6,530 circular mils) is thicker than 14 AWG (4,110 circular mils) and carries more current: 20 amps versus 15 at the 60 degree column.
How many amps can 12 gauge wire handle?
12 AWG copper handles 20 amps at the 60 degree column, 25 at 75 degrees, and 30 at 90 degrees per NEC 310.16. In residential work, NEC 240.4(D) caps the breaker at 20 amps on 12 AWG. Long runs may need a bigger size for voltage drop even when the amps are fine.
How many amps can 10 gauge wire handle?
10 AWG copper handles 30 amps at the 60 degree column, 35 at 75 degrees, and 40 at 90 degrees. NEC 240.4(D) caps the breaker at 30 amps for 10 AWG in most residential circuits. It is the standard size for 30 amp dryer and water heater circuits.
Why do I need bigger wire for a long run?
Wire resistance adds up with distance, so a long run drops more voltage before it reaches the load. A 100 foot, 15 amp run on 12 AWG copper drops 5.93 volts (4.94 percent), past the NEC 3 percent guidance. Upsizing to 8 AWG cuts the drop to 2.34 volts (1.95 percent). Size for ampacity first, then check voltage drop.