Wire Gauge Chart: AWG Sizes in Inches and mm

AWG (American Wire Gauge) is the US standard for the thickness of electrical wire. The numbers run backwards: the higher the gauge, the thinner the wire. That’s because the gauge originally counted how many times the wire was drawn through a die, and each pass made it thinner.

Choosing wire for a circuit? The wire size calculator gives the gauge for your amps and distance, including voltage drop.

AWG wire gauge chart

Diameters are for solid wire; stranded wire of the same gauge has the same copper area but measures slightly bigger across.

AWG	Diameter (in)	Diameter (mm)	Area (mm²)	Common use
4/0 (0000)	0.460	11.68	107.2	Service entrance (aluminum)
3/0 (000)	0.410	10.40	85.0	Service entrance, large feeders
2/0 (00)	0.365	9.27	67.4	Feeders, battery cables
1/0 (0)	0.325	8.25	53.5	Feeders, car audio power
1	0.289	7.35	42.4	Feeders
2	0.258	6.54	33.6	Subpanels
4	0.204	5.19	21.2	Subpanels, large appliances
6	0.162	4.11	13.3	Ranges, EV chargers (50 A)
8	0.128	3.26	8.37	Ranges, cooktops (40 A)
10	0.102	2.59	5.26	Dryers, water heaters (30 A)
12	0.081	2.05	3.31	Kitchen and bath outlets (20 A)
14	0.064	1.63	2.08	Lighting and outlets (15 A)
16	0.051	1.29	1.31	Extension cords, speaker wire
18	0.040	1.02	0.82	Lamp cords, thermostats
20	0.032	0.81	0.52	Doorbells, electronics, jewelry wire
22	0.025	0.64	0.33	Electronics, hookup wire
24	0.020	0.51	0.21	Ethernet (Cat 5e), phone wire
26	0.016	0.40	0.13	Patch cables, small electronics
28	0.013	0.32	0.08	Ribbon cable, fine electronics
30	0.010	0.25	0.05	Wire wrap, very fine work

The sizes follow a formula: diameter = 0.005 in × 92^((36 − AWG) / 39). Two rules of thumb fall out of it: every 6 gauges halves the diameter, and every 3 gauges halves the cross-section (and doubles the resistance).

Wire gauge for US home circuits

Circuit	Copper wire	Typical uses
15 A	14 AWG	Lighting, bedroom and living room outlets
20 A	12 AWG	Kitchen, bathroom, laundry and garage outlets
30 A	10 AWG	Electric dryers, water heaters, small AC units
40 A	8 AWG	Ranges, cooktops, wall ovens
50 A	6 AWG	Ranges, EV chargers, hot tubs

The first three are fixed by the US National Electrical Code’s small-conductor rule: 14, 12 and 10 AWG copper may not be protected by breakers bigger than 15, 20 and 30 amps. The larger sizes depend on the cable type and its temperature rating, so they’re typical values, not a rule. Aluminum wire needs to be about two sizes thicker than copper for the same current. For anything beyond replacing like with like, check your local code or hire a licensed electrician.

AWG to mm² and other gauges

Outside North America, wire is sold by cross-section in mm² instead of gauge. The nearest metric sizes:

AWG	Area	Nearest metric size
18	0.82 mm²	0.75 mm²
16	1.31 mm²	1.5 mm²
14	2.08 mm²	2.5 mm²
12	3.31 mm²	4 mm²
10	5.26 mm²	6 mm²
8	8.37 mm²	10 mm²
6	13.3 mm²	16 mm²

When swapping, go up to the bigger metric size, never down. Note that the British SWG (Standard Wire Gauge), still used for some craft and jewelry wire, has different numbers: 20 SWG is 0.91 mm, while 20 AWG is 0.81 mm.

How to measure a wire’s gauge

1. Strip a short piece of insulation, or look for the gauge printed on the jacket (for example “12-2 WITH GROUND” means two 12 AWG conductors plus a ground).
2. Measure across the bare copper with calipers, or count turns: wrap the wire tightly around a pencil 10 times, measure the width of the coil on a mm ruler, and divide by 10.
3. Find the closest diameter in the chart. For stranded wire, a wire-stripper’s gauge holes are the easiest check.

Choosing a cord rather than house wiring? See the extension cord gauge chart for which gauge suits each length and tool.

More DIY charts: extension cord gauge · sheet metal gauge · screw and bolt sizes · pipe sizes.