What is Wire Gauge : Chart, Measurement & Its Applications

We know that wire is used to transfer the current to a certain distance through less amount of resistance. So, the size of the wire mainly depends on the application because if you need huge power, the wire size should be larger. So, knowing the wire capacity through wire gauge is significant to know how much current an electric wire can carry without being injured. It is used to measure the cross-sectional area of a wire using the AWG (American Wire Gauge System) number. So, this article discusses an overview of a wire gauge, chart, and its applications.

Definition of Wire Gauge ?

The measurement of wire either its cross-sectional area or its diameter is known as wire gauge. The wire’s gauge determines how much current can supply throughout the wire, the wire’s resistance & its weight for each unit of length.

When using this gauge, the wire characteristics can be generally specified on a gauge chart which includes its diameter, size, area, ohms per 1000ft, feet per pound & capacity of current in amps. The wire gauge diagram is shown below.

Wire Gauge
Wire Gauge

The AWG system regulates the cross-sectional region of wires by allocating them an AWG number. In the following figure, a gauge wire with a less numbered wire includes a larger diameter, so it can able to carry maximum currents.

How to Measure Wire Gauge

Generally, these are accessible in two shapes like a circular otherwise oblong which includes notches through edges of the shape where every notch is stamped by wire size number. This is used to find out the width of sheet metal which is available from 0.1mm to 10mm.

The following diagram shows the gauge with stamped and different sizes on the notches. So let’s see how to measure the wire diameter otherwise sheet thickness using this gauge.

How to Measure Wire Gauge
How to Measure Wire Gauge

The following steps involve measuring wire gauges.

  • First, we have to check whether the tool for the measurement of gauge supports AWG or MWG.
  • Clip the gauge wire end, and then cut the boundary of the covering to expose the wire.
  • Take the wire or Sheet and place it into the notch. Once it is inserted then it must pass throughout the notch.
  • Place the exposed wire into a hole on the measurement tool of the gauge that tightly fits the wire. Make sure not to place one of the filaments of wire into a measurement hole that is very small because it may get bent.
  • On the outside of the hole, read the measurement on the tool to obtain the measurement of the gauge for the wire.

The standard AWG gauge sizes are available based on the quantity of currency you require for a particular application. So commonly used some of the AWG gauge sizes include the following.

  • 2-gauge wire
  • 6-gauge wire
  • 8- gauge wire
  • 10-gauge wire
  • 12-gauge wire
  • 14-gauge wire

Wire Gauge Chart

In the following gauge chart, there are 40 different gauge sizes available with diameter, area, feet per pound bare, Ohms per 1000ft 25°C, and current capacity in Amps.

Wire Size

The first column in the following table is wire size which specifies the size of wire from 4 to 40.


The diameter is twice the radius length of a wire’s circle diameter. The highest size of wire is if an AWG size is 4 whereas the smallest size of wire is if AWG size is 40.

The diameter of the wire can be expressed in different ways like inches, MILs, millimeters. Here, 1 mil is equivalent to 0.0254 mm or 0.001 inches.


The area of a wire is an area of its cross-section. This is calculated by the typical area of a circle, A=πr2. The area is specified in CM, circular MIL. A circular mil is a unit of area equal to that of a 1-mil-diameter circle. The CM area of a wire is the square of the MIL diameter.

Feet for Each Pound

A foot for every pound is the no. of feet that a gauge will give you for each 1lb of weight. For instance, AWG 4 wire is the biggest wire, thus it uses simply 7.918 feet of wire to 1lb weight. Meanwhile, AWG 40 wire is the smallest wire, so it uses 34,364 feet of wire to 1lb weight.

The wire weight can be determined through a god measure like feet per pound. So it will be used if the number of feet of the wire required is known.

Ohms for Every 1000ft

It is a measure of the wire’s resistance, used to determine the resistance of a wire. If the wire size and distance are longer, then more electrons hit each other & the walls of the wire. So this will create heat & friction to form resistance. With greater resistance, this diminishes current capacity.

If the wire length is shorter, then it will make less resistance. If the wire length is longer then it creates high resistance. In the following table, you can observe that the resistance of 1000 feet AWG4 wire is 0.2485Ω whereas AWG 40 wire has 1079Ω resistance for every 1000 feet.

Current Capacity in Amps

The current capacity of a wire can be defined as the amount of flow of current a wire can carry safely. The larger wires carry more current whereas smaller wires carry less current. In the tabular form, an AWG 4 wire carries 59.626 A of current very securely whereas AWG 40 wire carries 0.014mA of current very securely. If the limit of current in a wire increases the wire may get damaged, melt, or overload.

AWG Wire Size

 Diameter (MILs) Area


Feet for Each Pound


Ohms for Every 1000ft


Current Capacity in Amps



204.4 41738.50 7.920 0.2488 59.630


128.7 16512.26 25.24 0.7925 18.696
10 101.9 10383.61 31.82 0.9987


12 80.8 6528.64 50.61 1.5880



64.1 4108.81 80.39 2.5240 5.870


40.3 1624.09 203.5 6.3860


20 32 1024.00 222.7 10.1280



25.3 640.09 516.3 16.2000 0.914
24 20.1 404.01 817.7 25.6700



12.6 158.76 2081 65.3100 0.227
32 8.0 64.00 5163 162.0000



3.1 9.61 34364 1079.0000



The advantages of wire gauge include the following.

  • Fire hazards can be avoided
  • To avoid damage
  • Wires with bigger diameters can stay cooler.
  • Bigger wires provide extra benefits


The disadvantages of wire gauge include the following.

  • If a small size gauge is used, then it may get damaged due to the huge current flow through it.
  • The cost of the wire varies based on the material used in the wire.
  • Less flexible.


The applications of wire gauge include the following.

  • These are used to carry or transport electrical current.
  • It measures the cross-sectional area of wire so that we can find out how much current an electric wire can supply without being damaged.
  • These are used to connect two stereo speakers to a major stereo unit and also to provide grounding wires for equipment
  • If the wrong gauge is utilized, it can cause the wire to melt or overheat. Consequently, building codes within all developing & developed nations need inspectors or exterior authorities to confirm the right gauge is used for a new design or modifying work on structures.
  • 18 size gauge is used in lamp cords & other less voltage lighting fixtures.
  • 14 size is used mainly for light fixtures, lamps & 15 amps lighting circuits.
  • 16 size is suitable for extension cords which supports 13 A.
  • 12 size is perfect to utilize in the kitchen, bathroom, outside receptacles, etc.
  • 10 size is most frequently used in water heaters, clothes dryers & 240V window ACs.
  • 6 size is suitable for cooktops which carrier from 40 to 50 A
  • 4-gauge is mainly used for electric heaters which are protected at 60 A.

What does gauge mean in a wire?

The wire gauge mainly refers to its thickness. Every gauge can be signified through a number. The smaller numbers represent thicker gauges whereas higher numbers signify thinner wires.

What gauge is standard electrical wiring?

The most common gauges sizes used in residential work are 12-gauge & 14-gauge. Large appliances like electric water heaters, electric stoves, central air units, and electric dryers frequently use 6, 8 & 10 gauge wires.

Can you use two different gauge wires together?

No, we should never use two different gauge wires because overloading a wire could cause it to melt, overheat, etc.

How do you determine wire gauge size?

To determine the gauge size, first, you need twice the diameter. Thus if you have calculated the diameter of the wire to be 0.5 inches, then multiply this diameter value by itself, so the result value will be 0.25. Multiply this result value by the number of strands within the wire.

Thus, this is all about an overview of wire gauge and its chart with applications. The main function of this is to measure the cross-sectional area of the wire. So it is very important to know the gauge to determine how much flow of current an electric wire can hold without being smashed. Here is a question for you, what are the types of wire gauges?