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Electrical conductor geometry

AWG Wire Size Chart

Look up solid-wire diameter, cross-sectional area, circular mils, and metric equivalents from 4/0 through 40 AWG, then filter or compare gauges.

Range
4/0–40 AWG
Basis
Solid round wire
Rows
44 gauge sizes

Primary reference

AWG diameter and area table

Calculated nominal geometry for solid round wire.

Search a gauge such as “12 AWG,” filter by size band, or open advanced tools to find gauges near a target cross-sectional area. Select rows to compare them in the chart.

Scroll horizontally to view additional columns and vertically to view additional rows. Column headers remain visible while scrolling.

American Wire Gauge sizes 4/0 through 40 with formula index, bare solid-wire diameter, circular-mil area, and square-millimeter area.
4/0 -3 0.4600 11.684 211,600 107.2
3/0 -2 0.4096 10.405 167,806 85.0
2/0 -1 0.3648 9.266 133,077 67.4
1/0 0 0.3249 8.251 105,535 53.5
1 1 0.2893 7.348 83,693 42.4
2 2 0.2576 6.544 66,371 33.6
3 3 0.2294 5.827 52,635 26.7
4 4 0.2043 5.189 41,741 21.2
5 5 0.1819 4.621 33,102 16.8
6 6 0.1620 4.115 26,251 13.3
7 7 0.1443 3.665 20,818 10.5
8 8 0.1285 3.264 16,510 8.37
9 9 0.1144 2.906 13,093 6.63
10 10 0.1019 2.588 10,383 5.26
11 11 0.09074 2.305 8,234 4.17
12 12 0.08081 2.053 6,530 3.31
13 13 0.07196 1.828 5,178 2.62
14 14 0.06408 1.628 4,107 2.08
15 15 0.05707 1.450 3,257 1.65
16 16 0.05082 1.291 2,583 1.31
17 17 0.04526 1.150 2,048 1.04
18 18 0.04030 1.024 1,624 0.823
19 19 0.03589 0.9116 1,288 0.653
20 20 0.03196 0.8118 1,022 0.518
21 21 0.02846 0.7229 810 0.410
22 22 0.02535 0.6438 642 0.326
23 23 0.02257 0.5733 509 0.258
24 24 0.02010 0.5106 404 0.205
25 25 0.01790 0.4547 320 0.162
26 26 0.01594 0.4049 254 0.129
27 27 0.01420 0.3606 202 0.102
28 28 0.01264 0.3211 160 0.0810
29 29 0.01126 0.2859 127 0.0642
30 30 0.01003 0.2546 101 0.0509
31 31 0.008928 0.2268 80 0.0404
32 32 0.007950 0.2019 63 0.0320
33 33 0.007080 0.1798 50 0.0254
34 34 0.006305 0.1601 40 0.0201
35 35 0.005615 0.1426 32 0.0160
36 36 0.005000 0.1270 25 0.0127
37 37 0.004453 0.1131 20 0.0100
38 38 0.003965 0.1007 16 0.0080
39 39 0.003531 0.0897 12 0.0063
40 40 0.003145 0.0799 10 0.0050

Values describe the nominal bare conductor geometry of a solid round wire. Insulation thickness, finished cable outside diameter, strand construction, resistance, temperature rating, and allowable ampacity are outside this table’s scope.

Area lookup and table actions

How to read the scale

A larger AWG number means a smaller wire

  • Gauge direction: 4/0 is the largest size shown; 40 AWG is the smallest.
  • Six-gauge shortcut: moving six gauge numbers changes diameter by about a factor of two; area changes by about a factor of four.
  • Three-gauge shortcut: moving three sizes changes cross-sectional area by about a factor of two.
  • Designation: 1/0, 2/0, 3/0, and 4/0 are also called one-aught through four-aught.

What this chart does—and does not—select

This chart answers a geometry question: the nominal diameter and metallic cross-sectional area associated with an AWG designation. It does not determine whether a conductor is suitable for a circuit.

Design boundary

Do not infer ampacity from diameter alone. Conductor material, insulation temperature rating, number of current-carrying conductors, ambient temperature, installation method, terminal ratings, voltage drop, and governing code all affect a final wire selection.

AWG formula and unit conversions

The AWG progression is geometric. With n = 36 for 36 AWG, n = 0 for 1/0, and negative indices for larger aught sizes, the nominal diameter is:

Diameter in inchesd = 0.005 × 92(36 − n) / 39

The endpoints are 0.005 inch at 36 AWG and 0.460 inch at 4/0 AWG.

Diameter conversion
dmm = 25.4 × din
Circular mils
cmil = (1,000 × din)²
Metric area
A = πdmm² / 4

Calculations use unrounded formula values internally; displayed values are rounded only at the end. Circular mil is an area unit, even though its definition uses a diameter measured in mils.

Worked AWG lookup examples

Convert 12 AWG to metric area

The table gives a nominal diameter of 2.053 mm. Applying A = πd²/4 gives about 3.31 mm². This is metallic area, not insulated cable outside diameter.

Find a gauge near 2.5 mm²

Enter 2.5 in Minimum area. The nearest listed nominal area is 13 AWG at about 2.62 mm²; 14 AWG is about 2.08 mm². A code-compliant conductor choice still requires the applicable ampacity and installation rules.

Compare 10 and 16 AWG

10 AWG is about 2.588 mm in diameter and 5.26 mm² in area; 16 AWG is about 1.291 mm and 1.31 mm². Six gauge steps nearly halve diameter and quarter area.

AWG data basis and engineering references

Dataset scope: formula-derived nominal geometry for 44 solid round-wire sizes, 4/0 through 40 AWG.

The page uses the defining AWG geometric progression and calculates the converted fields shown in the table. It does not reproduce resistance, mass, strength, or ampacity tables.

Dataset and source-check details

Edition / formulation
ASTM B258-18(2026) scope; AWG geometric progression from 4/0 to 40
Source-controlled fields
ASTM subject scope; NBS Handbook 100 gauge endpoints, progression, and unit conventions
Calculated fields
Diameter conversions, circular mils, and square-millimeter area
Reference conditions
Nominal bare solid round-wire geometry
Known exclusions
Ampacity, resistance, material, stranding, insulation, cable OD, and code selection
Rights / download
Original calculated dataset; visible-row CSV permitted with source attribution retained on page
Source check
Source scope checked August 9, 2026
Publisher
Turn2Engineering

AWG wire size questions

No. AWG numbering runs in the opposite direction: a higher gauge number means a smaller conductor diameter and area.

Use geometry first, then verify the electrical design

Use this AWG wire size chart to translate a gauge designation into nominal solid-wire diameter and area or to locate the closest listed geometry. For an actual circuit, continue with ampacity, voltage-drop, terminal, insulation, raceway-fill, and code checks.

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