How to Read Wire Gauge Sizes
Understanding wire gauge sizes is important when choosing electrical wire for a circuit, appliance, or wiring project. Wire gauge tells you the diameter and thickness of a wire, and it can help you determine how much electrical current the wire can safely carry.
In the United States, wire sizes are commonly identified using the American Wire Gauge (AWG) system.
What Does Wire Gauge Mean?
Wire gauge is a standardized way of describing the size of a wire. One important thing to remember is that a smaller AWG number means a thicker wire.
For example:
14 AWG is thicker than 16 AWG
12 AWG is thicker than 14 AWG
10 AWG is thicker than 12 AWG
8 AWG is thicker than 10 AWG
As the gauge number decreases, the wire diameter increases.
How to Read an AWG Wire Size
Look for the AWG number printed on the wire insulation, packaging, or cable specifications.
For example, if a cable is marked 12 AWG, it means the conductor has a standardized American Wire Gauge size of 12.
A smaller number indicates a larger conductor:
8 AWG → 10 AWG → 12 AWG → 14 AWG → 16 AWG
The wire becomes progressively thinner as the AWG number increases.
Common Wire Gauge Sizes
Some commonly used AWG sizes include:
| AWG Size | Relative Thickness | Common Uses |
|---|---|---|
| 6 AWG | Very thick | Large electrical loads |
| 8 AWG | Thick | Large appliances and circuits |
| 10 AWG | Medium-thick | Higher-current circuits |
| 12 AWG | Medium | General-purpose circuits |
| 14 AWG | Thinner | Lighting and smaller circuits |
| 16 AWG | Thin | Low-power applications |
| 18 AWG | Very thin | Electronics and control wiring |
The appropriate wire size depends on more than gauge alone. Current, voltage, conductor material, installation conditions, and local electrical codes can all affect the correct choice.
Does a Higher Gauge Mean a Bigger Wire?
No. This is one of the most common mistakes when reading wire sizes.
With the AWG system, higher numbers mean smaller wires. Therefore, 10 AWG is larger than 14 AWG.
If you’re comparing two wires, remember:
Lower AWG number = thicker wire
Higher AWG number = thinner wire
How to Find the Wire Gauge
If the wire has markings, check the insulation for information such as 12 AWG, 14 AWG, or another size designation.
If there is no visible marking, you can measure the conductor diameter and compare it with an AWG wire size chart. Keep in mind that measuring a stranded wire can be less straightforward because of the way the individual strands are arranged.
For a faster way to determine the corresponding wire size from a conductor measurement, you can use a wire gauge calculator.
Why Wire Gauge Matters
Choosing the correct wire size is important for electrical safety and performance. A wire that is too small for the current it carries can experience excessive heating and voltage drop.
Wire gauge is therefore only one part of selecting a suitable conductor. Always check the applicable electrical code and the manufacturer’s specifications before installing electrical wiring.