Copper Wire Properties & Gauge Conversions

Values presented here are standards available for many independent publications, but ultimately they all originate from the American Wire Gauge (AWG) system (also aka the Brown and Sharp gauge). It has been in existence since the mid 1800s in the U.S. and Canada.

Note that as wire gauge number is increased the wire diameter decreases. Although it might seem somewhat backward, there is a good reason for it. Originally, it was related to the number of time a wire needed to be drawn through an extraction die in order to achieve the final wire size.

By definition, 36 AWG is 0.0050 inches in diameter, and 0000 is 0.4600 inches in diameter. The ratio of these diameters is 92, and there are 40 gauge sizes from #36 to #0000, or 39 steps. Using this ratio, wire gauge sizes vary geometrically according to the following formula: The diameter of an n AWG wire is:

Accordingly, the ASTM B 258-02 standard defines the ratio between successive sizes to be the 39th root of 92, or approximately 1.1229322.

Stranding designation of a/b means a number of b gauge wires. E.g., 7/44 means 7 strands of 44 AWG solid wire.

Note: Just a 3 dB change in power represents a doubling (or halving) of power, a change of 3 wire sizes represents approximately a doubling (or halving) of cross-sectional area.

See wire gauge conversion chart at bottom of page.  Values given at 25 °C.

AWG	Stranding	Approx. 0.D.		Circular Mil Area	Weight (lbs/1000 ft)	Weight (kg/km)	Resistance (Ω/1000 ft)	Resistance (Ω/km)
		Inches	mm
40	Solid	0.003145	0.07988	9.888	0.02993
39	Solid	0.003531	0.08969	12.47	0.03774
38	Solid	0.003965	0.1007	15.72	0.04759
37	Solid	0.004453	0.1131	19.83	0.06001
36	Solid	0.005000	0.1270	25.00	0.07568	0.113	445.0	1460.0
36	7/44	0.0060	0.152	28.0	0.085	0.126	371.0	1271.0
35	Solid	0.005614		31.52	0.09542
34	Solid	0.006304	0.1601	39.75	0.1203	0.179	280.0	9180.0
34	7/42	0.0075	0.192	43.8	0.132	0.196	237.0	777.0
33	Solid	0.007080	0.1798	50.13	0.1517
32	Solid	0.007950	0.2019	63.21	0.1913	0.289	174.0	571.0
32	7/40	0.008	0.203	67.3	0.203	0.302	164.0	538.0
32	19/44	0.009	0.229	76.0	0.230	0.342	136.0	448.0
31	Solid	0.007950	0.2268	79.70	0.2413
30	Solid	0.01003	0.2548	100.5	0.3042	0.45	113.0	365.0
30	7/38	0.012	0.305	112.0	0.339	0.504	103.0	339.0
30	19/42	0.012	0.305	118.0	0.359	0.534	87.3	286.7
29	Solid	0.01126	0.2860	126.7	0.3836
28	Solid	0.01246	0.3211	159.8	0.4837	0.72	70.8	232.0
28	7/36	0.015	0.381	175.0	0.529	0.787	64.9	213.0
28	19/40	0.016	0.406	182.6	0.553	0.823	56.7	186.0
27	Solid	0.01419	0.3604	201.5	0.6100
27	7/35	0.018	0.457	219.1	0.664	0.988	54.5	179.0
26	Solid	0.01594	0.4049	254.1	0.7692	1.14	43.6	143.0
26	10/36	0.021	0.533	250.0	0.757	1.13	41.5	137.0
26	19/38	0.020	0.508	304.0	0.920	1.37	34.4	113.0
26	7/34	0.019	0.483	277.1	0.841	1.25	37.3	122.0
25	Solid	0.01790	0.4547	320.4	0.9699
24	Solid	0.02010	0.5105	404.0	1.223	1.82	27.3	89.4
24	7/32	0.024	0.610	448.0	1.36	2.02	23.3	76.4
24	10/34	0.023	0.582	396.1	1.20	1.79	26.1	85.6
24	19/36	0.024	0.610	475.0	1.43	2.13	21.1	69.2
24	41/40	0.023	0.582	384.4	1.16	1.73	25.6	84.0
23	Solid	0.02257	0.5733	509.5	1.542
22	Solid	0.02535	0.6439	642.4	1.945	2.91	16.8	55.3
22	7/30	0.030	0.762	700.0	2.12	3.16	14.7	48.4
22	19/34	0.031	0.787	754.1	2.28	3.39	13.7	45.1
22	26/36	0.030	0.762	650.0	1.97	2.93	15.9	52.3
21	Solid	0.02846	0.7229	810.1	2.452
20	Solid	0.03196	0.8118	1022	3.092	4.61	10.5	34.6
20	7/28	0.038	0.965	1111	3.49	5.19	10.3	33.8
20	10/30	0.035	0.889	1000	3.03	4.05	10.3	33.9
20	19/32	0.037	0.940	1216	3.70	5.48	8.6	28.3
20	26/34	0.036	0.914	1031	3.12	4.64	10.0	33.0
20	41/36	0.036	0.914	1025	3.10	4.61	10.0	32.9
19	Solid	0.03589	0.9116	1288	3.899
18	Solid	0.0403	1.024	1624	4.917	7.32	6.6	21.8
18	7/26	0.048	1.219	1769	5.36	7.98	5.9	19.2
18	16/30	0.047	1.194	1600	4.84	7.20	8.5	21.3
18	19/30	0.049	1.245	1900	5.75	8.56	5.5	17.9
18	41/34	0.047	1.194	1627	4.92	7.32	6.4	20.9
18	65/36	0.047	1.194	1625	4.91	7.31	6.4	21.0
17	Solid	0.04526	1.150	2048	6.200
16	Solid	0.05082	1.291	2583	7.818	11.60	4.2	13.7
16	7/24	0.060	1.524	2828	8.56	12.74	3.7	12.0
16	65/34	0.059	1.499	2579	7.81	11.62	4.0	13.2
16	26/30	0.059	1.499	2600	7.87	11.71	4.0	13.1
16	19/29	0.058	1.473	2426	7.35	10.94	4.3	14.0
16	105/36	0.059	1.499	2625	7.95	11.83	4.0	13.1
15	Solid	0.05707	1.450	3257	12.43
14	Solid	0.06408	1.628	4107	12.43	18.50	2.6	8.6
14	7/22	0.073	1.854	4480	13.56	20.18	2.3	7.6
14	19/27	0.073	1.854	3830	11.59	17.25	2.7	8.9
14	41/30	0.073	1.854	4100	12.40	18.45	2.5	8.3
14	105/34	0.073	1.854	4167	12.61	18.77	2.5	8.2
13	Solid	0.07196	1.828	5178	15.68
12	Solid	0.08081	2.053	6530	19.77
11	Solid	0.09074	2.305	8234	24.92
10	Solid	0.1019	2.588	10380	31.43
9	Solid	0.1144	2.906	13090	39.63
8	Solid	0.1285	3.264	16510	49.98
7	Solid	0.1443	3.665	20820	63.02
6	Solid	0.1620	4.115	26250	79.46
5	Solid	0.1819	4.620	33100	100.2
4	Solid	0.2043	5.189	41740	126.4
3	Solid	0.2294	5.827	52640	159.3
2	Solid	0.2576	6.543	66370	200.9
1	Solid	0.2893	7.348	83690	253.3
0	Solid	0.3249	8.252	105500	319.5
00	Solid	0.3648	9.266	133100	402.8
000	Solid	0.4096	10.40	167800	507.9
0000	Solid	0.4600	11.68	211600	640.5

Wire Gauge Conversions

All Units Are in Inches

GAUGE #	AWG	W & M	SWG	BWG	U.S. Standard
7/0	0.6513	0.490	0.500		0.5000
6/0	0.5800	0.460	0.464		0.4688
5/0	0.5165	0.430	0.432		0.4375
4/0	0.4600	0.3938	0.400	0.454	0.4063
3/0	0.4096	0.3625	0.372	0.425	0.3750
2/0	0.3648	0.3310	0.348	0.380	0.3438
1/0	0.3249	0.3065	0.324	0.340	0.3125
1	0.2893	0.2830	0.300	0.300	0.2813
2	0.2576	0.2625	0.276	0.284	0.2656
3	0.2294	0.2437	0.252	0.259	0.2391
4	0.2043	0.2253	0.232	0.238	0.2242
5	0.1819	0.2070	0.212	0.220	0.2092
6	0.1620	0.1920	0.192	0.203	0.1943
7	0.1443	0.1770	0.176	0.180	0.1793
8	0.1285	0.1620	0.160	0.165	0.1644
9	0.1144	0.1483	0.144	0.148	0.1495
10	0.1019	0.1350	0.128	0.134	0.1345
11	0.0907	0.1205	0.116	0.120	0.1196
12	0.0808	0.1055	0.104	0.109	0.1046
13	0.0719	0.0915	0.092	0.095	0.0897
14	0.0641	0.0800	0.080	0.083	0.0747
15	0.0571	0.0720	0.072	0.072	0.0673
16	0.0508	0.0625	0.064	0.065	0.0598
17	0.04526	0.054	0.056	0.058	0.0538
18	0.04030	0.0475	0.048	0.049	0.0478
19	0.03589	0.0410	0.040	0.042	0.0418
20	0.03196	0.0348	0.036	0.035	0.0359
21	0.02846	0.03175	0.032	0.032	0.0329
22	0.02535	0.0286	0.028	0.028	0.0299
23	0.02257	0.0258	0.024	0.025	0.0269
24	0.02010	0.0230	0.022	0.022	0.0239
25	0.01790	0.0204	0.020	0.020	0.0209
26	0.01594	0.0181	0.018	0.018	0.0179
27	0.01420	0.0173	0.0164	0.016	0.0164
28	0.01264	0.0162	0.0148	0.014	0.0149
29	0.01126	0.0150	0.0136	0.013	0.0135
30	0.0103	0.014	0.0124	0.012	0.0120
31	0.00893	0.0132	0.0116	0.010	0.0109
32	0.00795	0.0128	0.0108	0.009	0.0102
33	0.00708	0.0118	0.0100	0.008	0.0094
34	0.00630	0.0104	0.0092	0.007	0.0086
35	0.00561	0.0095	0.0084	0.005	0.0078
36	0.00500	0.0090	0.0076	0.004	0.0070
37	0.00445	0.0085	0.0068
38	0.00396	0.0080	0.0060
39	0.00353	0.0075	0.0052
40	0.00314	0.007	0.0048
41	0.00279	0.0066	0.0044
42	0.00249	0.0062	0.0040
43	0.00221	0.0060	0.0036
44	0.00198	0.0058	0.0032
45	0.00176	0.0055	0.0028
46	0.00157	0.0052	0.0024
47	0.00140	0.0050	0.0016
48	0.00124	0.0048	0.0012
49	0.00111	0.0046	0.0010
50	0.00099	0.0044
51	0.00088
52	0.00078
53	0.00070
54	0.00060
55	0.00050
56	0.00040
AWG = American Wire Gauge (Brown & Sharpe) W & M = Washburn & Moen (steel wire gauge) SWG = Imperial Standard Wire Gauge BWG = Birmingham or Stubs Wire Gauge US Standard = United States Standard (Revised)