When working with electrical wiring, one of the most important things to understand is the American Wire Gauge (AWG) system. Whether you’re an electrician, engineer, or DIY enthusiast, knowing how wire gauges convert into actual physical sizes in inches and millimeters is essential. The AWG chart provides a standardized system for measuring the diameter of round, solid, nonferrous, electrically conducting wire.
In this article, we’ll explain what AWG is, why it matters, and provide a complete AWG conversion chart that shows wire sizes in both inches and millimeters.
What is American Wire Gauge (AWG)?
American Wire Gauge (AWG) is a standardized wire measurement system developed in the United States in 1857. It is used primarily in North America to specify wire diameters. Instead of random sizing, AWG assigns numbers to wire diameters in a consistent way:
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Smaller numbers = thicker wires
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Larger numbers = thinner wires
For example, AWG 0000 (4/0) is a very thick cable used for heavy-duty electrical work, while AWG 40 or higher is extremely thin, often used in delicate electronics.
Why AWG Matters
Understanding AWG is critical because wire diameter directly affects:
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Current capacity (ampacity) – Thicker wires can carry more electrical current safely.
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Resistance – Smaller wires have higher resistance, leading to voltage drops.
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Applications – Choosing the wrong wire gauge could result in overheating, equipment damage, or even electrical fires.
For example:
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AWG 14 is commonly used in residential lighting circuits.
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AWG 12 is used for outlets and appliances.
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AWG 4/0 is used for large-scale power transmission.
American Wire Gauge Conversion Chart (AWG)
Below is a detailed AWG conversion chart, showing wire gauge numbers alongside their equivalent diameters in inches and millimeters.
| Gauge No. | Inches | Millimeters |
|---|---|---|
| 7/0 | 0.651300 | 16.54 |
| 6/0 | 0.580049 | 14.73 |
| 5/0 | 0.516549 | 13.12 |
| 4/0 | 0.460000 | 11.68 |
| 3/0 | 0.409642 | 10.40 |
| 2/0 | 0.364797 | 9.266 |
| 1/0 | 0.324861 | 8.251 |
| 1 | 0.289297 | 7.348 |
| 2 | 0.257626 | 6.544 |
| 3 | 0.229423 | 5.827 |
| 4 | 0.204307 | 5.189 |
| 5 | 0.181941 | 4.621 |
| 6 | 0.162023 | 4.115 |
| 7 | 0.144285 | 3.665 |
| 8 | 0.128490 | 3.264 |
| 9 | 0.114424 | 2.906 |
| 10 | 0.101897 | 2.588 |
| 11 | 0.090742 | 2.305 |
| 12 | 0.080808 | 2.053 |
| 13 | 0.071962 | 1.828 |
| 14 | 0.064084 | 1.628 |
| 15 | 0.057068 | 1.450 |
| 16 | 0.050821 | 1.291 |
| 17 | 0.045257 | 1.150 |
| 18 | 0.040303 | 1.024 |
| 19 | 0.035891 | 0.9116 |
| 20 | 0.031961 | 0.8118 |
| 21 | 0.028462 | 0.7229 |
| 22 | 0.025347 | 0.6438 |
| 23 | 0.022572 | 0.5733 |
| 24 | 0.020101 | 0.5106 |
| 25 | 0.017900 | 0.4547 |
| 26 | 0.015941 | 0.4049 |
| 27 | 0.014196 | 0.3606 |
| 28 | 0.012641 | 0.3211 |
| 29 | 0.011258 | 0.2860 |
| 30 | 0.010025 | 0.2546 |
| 31 | 0.008928 | 0.2268 |
| 32 | 0.007950 | 0.2019 |
| 33 | 0.007080 | 0.1798 |
| 34 | 0.006305 | 0.1601 |
| 35 | 0.005615 | 0.1426 |
| 36 | 0.005000 | 0.1270 |
| 37 | 0.004453 | 0.1131 |
| 38 | 0.003965 | 0.1007 |
| 39 | 0.003531 | 0.08969 |
| 40 | 0.003145 | 0.07988 |
| 41 | 0.002800 | 0.07112 |
| 42 | 0.002494 | 0.06335 |
| 43 | 0.002221 | 0.05641 |
| 44 | 0.001978 | 0.05024 |
| 45 | 0.001761 | 0.04473 |
| 46 | 0.001568 | 0.03983 |
| 47 | 0.001397 | 0.03548 |
| 48 | 0.001244 | 0.03160 |
| 49 | 0.001108 | 0.02814 |
| 50 | 0.000986 | 0.02504 |
| 51 | 0.000878 | 0.02230 |
| 52 | 0.000782 | 0.01986 |
| 53 | 0.000697 | 0.01770 |
| 54 | 0.000620 | 0.01575 |
| 55 | 0.000552 | 0.01402 |
| 56 | 0.000492 | 0.01250 |
| 57 | 0.000438 | 0.01113 |
| 58 | 0.000390 | 0.00991 |
| 59 | 0.000347 | 0.00881 |
| 60 | 0.000309 | 0.00785 |
How to Use the AWG Chart
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Identify the gauge number on your wire.
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Find the diameter in inches or millimeters from the chart.
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Use this to calculate ampacity (how much current the wire can safely handle).
For example:
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AWG 10 wire has a diameter of 0.1019 inches (2.588 mm) and is commonly rated for 30 amps in residential use.
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AWG 24 wire, with a diameter of 0.0201 inches (0.5106 mm), is used in telecommunication and low-power applications.
Try Our Free tool AWG to mm calculator
Final Thoughts
The American Wire Gauge (AWG) conversion chart is a vital reference for anyone working with electrical wiring. Understanding the relationship between gauge numbers, diameters, and their real-world applications ensures safer and more efficient projects.
Whenever you’re choosing a wire for a project—whether it’s household wiring, car audio systems, or industrial power transmission—use this chart to double-check that you’ve got the correct size.
Deven Kumar is the creator and lead writer of measurerealm.com, a site dedicated to helping readers understand everyday measurements and sizes through clear, relatable examples. With a knack for simplifying numbers and dimensions, Deven makes measurement concepts easy and interesting for everyone. Passionate about practical knowledge, Deven’s goal is to provide content that informs, educates, and adds value to daily life.