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Convert AWG gauge to mm and diameter. Use for sizing wire; for drop use voltage-drop-calculator. Input: AWG number. Returns specs. 100% client-side, files never leave browser.
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Converts between American Wire Gauge (AWG), millimeters squared (mm²), diameter in millimeters, and resistance per kilometer for the most common AWG sizes. Includes a quick-reference table for AWG 0000 through AWG 28 with their corresponding diameter, cross-section, and copper resistance.
Every electrician, engineer, and hobbyist has had to convert between AWG and mm² at some point. The conversion isn't linear (each AWG step changes by a fixed ratio, not a fixed amount), so mental math is impractical. This calculator gives the answer instantly, plus the diameter and resistance for the resulting size.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Electricians selecting wire size, electrical engineers designing harnesses, DIY solar / RV / boat owners picking battery cable gauge, audio / HiFi enthusiasts matching speaker wire, and electronics hobbyists converting between AWG and mm² when sourcing parts.
Pick a conversion mode (AWG→mm², mm²→AWG, AWG→diameter, or diameter→AWG)
Enter the value to convert (AWG accepts '12', '12 AWG', or '#12')
Read the result: primary value, secondary cross-section/diameter, and resistance
Open the AWG quick-reference table for a side-by-side look at the most common sizes
The result uses the standard AWG formula and copper at 20°C for resistance
AWG 12 → 3.309 mm², 2.053 mm diameter, 5.21 Ω/kmAWG 10 → 5.261 mm², 2.588 mm diameter, 3.28 Ω/kmAWG 14 → 2.081 mm², 1.628 mm diameter, 8.29 Ω/kmAWG 8 → 8.366 mm², 3.264 mm diameter, 2.06 Ω/km3.309 mm² → AWG 12 (exact)Is AWG a diameter or cross-section?
It's a gauge index, not a size. The standard formula is: area = 0.012668 mm² × 92^((36−n)/19.5), which means each AWG step is ~1.26× the area of the previous step.
Why is 0000 smaller than 0?
In AWG, higher numbers are thinner. 0000 (often written 4/0) is the largest at ~107 mm². 0 (1/0) is smaller. Negative AWG numbers: -4 = 0000, -3 = 000, -2 = 00, -1 = 0.
Does the calculator handle stranded wire?
No. AWG is defined for solid round wire. Stranded wire uses circular mils (CM) or the cross-section in mm². The calculator covers the solid-wire case.
What about aluminum?
Aluminum has ~1.54× the resistance of copper at the same cross-section. For voltage drop, use the voltage-drop calculator (which has a material toggle) rather than this one.
Is the resistance value accurate for AC?
The values shown are DC resistance at 20°C. AC resistance is slightly higher due to skin effect, especially for large conductors at high frequency.
Authoritative specifications, standards, and in-depth reading for Wire Gauge Calculator.
3.309 mm²
2.05 mm diameter
0.005211 Ω/km
AWG 12
| AWG | Diameter (mm) | Area (mm²) | Ω/km (Cu, 20°C) |
|---|---|---|---|
| 0000 (4/0) | 11.684 | 107.2 | 0.16 |
| 000 (3/0) | 10.405 | 85.01 | 0.2 |
| 00 (2/0) | 9.266 | 67.43 | 0.26 |
| 0 (1/0) | 8.252 | 53.49 | 0.32 |
| 1 | 7.348 | 42.41 | 0.41 |
| 2 | 6.544 | 33.62 | 0.51 |
| 4 | 5.189 | 21.15 | 0.82 |
| 6 | 4.115 | 13.3 | 1.3 |
| 8 | 3.264 | 8.366 | 2.06 |
| 10 | 2.588 | 5.261 | 3.28 |
| 12 | 2.053 | 3.309 | 5.21 |
| 14 | 1.628 | 2.081 | 8.29 |
| 16 | 1.291 | 1.309 | 13.18 |
| 18 | 1.024 | 0.823 | 20.95 |
| 20 | 0.812 | 0.518 | 33.3 |
| 22 | 0.644 | 0.326 | 52.96 |
| 24 | 0.511 | 0.205 | 84.22 |
| 26 | 0.405 | 0.129 | 134 |
| 28 | 0.321 | 0.081 | 213 |
Resistance values assume copper at 20°C (resistivity 1.7241×10⁻⁸ Ω·m). All math runs in your browser.
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