AWG wire gauge reference
American Wire Gauge (AWG) uses an inverse scale — the lower the number, the thicker the wire and the higher its current capacity. This table covers the gauges most commonly encountered in household wiring, extension cords, and appliances.
Household and appliance wiring
| AWG | Diameter (mm) | Max amps (60 °C) | Max watts @ 120V | Max watts @ 240V | Common uses |
|---|---|---|---|---|---|
| 18 | 1.02 | 7 A | 840 W | 1,680 W | Lamps, light fixtures, low-voltage |
| 16 | 1.29 | 10 A | 1,200 W | 2,400 W | Light fixtures, fans, small appliances |
| 14 | 1.63 | 15 A | 1,800 W | 3,600 W | Standard 15 A household circuits (outlets, lights) |
| 12 | 2.05 | 20 A | 2,400 W | 4,800 W | Kitchen, bath, laundry (20 A circuits) |
| 10 | 2.59 | 30 A | 3,600 W | 7,200 W | Dryers, AC units, water heaters |
| 8 | 3.26 | 40 A | 4,800 W | 9,600 W | Electric ranges, large AC units |
| 6 | 4.11 | 55 A | 6,600 W | 13,200 W | Sub-panels, EV chargers, large appliances |
Extension cord guide
Extension cords are rated differently because they are meant for temporary use. A cord that is too thin will overheat under load. Match the cord gauge to the amperage of the device.
| Cord AWG | Max amps | Max length (100 ft / 30 m) | Typical applications |
|---|---|---|---|
| 18 | 7 A / 840 W | Not recommended >25 ft at full load | Lamps, phone chargers, clocks |
| 16 | 10 A / 1,200 W | Up to 50 ft | Power tools (light), fans, small appliances |
| 14 | 15 A / 1,800 W | Up to 100 ft | Power tools, space heaters, shop equipment |
| 12 | 20 A / 2,400 W | 100–150 ft | High-draw tools, compressors, outdoor equipment |
| 10 | 30 A / 3,600 W | Up to 150 ft | Heavy shop tools, welders |
Speaker wire guide
| AWG | Resistance per 100 ft | Recommended max run | Notes |
|---|---|---|---|
| 24 | ~2.57 Ω | 25 ft | Very thin — short desktop runs only |
| 22 | ~1.62 Ω | 40 ft | Bookshelf speakers, short runs |
| 18 | ~0.64 Ω | 80 ft | Most home stereo use |
| 16 | ~0.40 Ω | 125 ft | Floor-standing speakers, longer runs |
| 14 | ~0.25 Ω | 200 ft | High-power amplifiers, in-wall runs |
| 12 | ~0.16 Ω | 300 ft | Commercial installs, very long runs |
Quick tip
How to read an extension cord label
Most extension cords print the gauge as AWG or as part of a code like 16/3 — which means 16 AWG wire with 3 conductors (hot, neutral, ground). A 3-conductor cord is suitable for grounded appliances; a 2-conductor cord is for ungrounded (polarized) loads like lamps.
Quick tip
Voltage drop rule of thumb
Resistance in the wire causes voltage to drop across the run, reducing available power at the device. The NEC recommends keeping voltage drop under 3% for branch circuits and under 5% total. For a 120 V, 15 A circuit, that means no more than 3.6 V of drop. Use a heavier gauge or shorter run when powering sensitive equipment.