The AWG Calculator is a user-friendly tool that allows you to determine various wire properties based on the selected AWG size and conductor material. Simply select the desired values from the dropdowns, optionally adjust the resistivity (if necessary), and click “Calculate” to instantly get the wire’s dimensions, cross-sectional area, mass, length, and resistance values.
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Notes:
- All calculations are correct if electrical conductors are used at the international standardized reference temperature of 20°C (68°F).
- The value of 875.20 Ω·lb/mile2 at 20°C (68°F) is the mass resistivity equivalent to the International Annealed Copper Standard (IACS) for 100 % conductivity.
Calculation Rules
For a better understanding of the table presented, I give formulas that you can also use in your own calculations.
Standard Nominal Diameters
In accordance with the standard ASTM B258-14, for wire sizes 4/0 to 10 AWG, inclusive, expressed in mil units, and for wire sizes 4/0 to 18 AWG, inclusive, expressed in millimetre units, nominal diameters shall be expressed in no more than four significant figures. For wire sizes 11 AWG and smaller, expressed in mil units, and for wire sizes in 19 AWG and smaller expressed in millimetre units, nominal diameters shall be expressed in no more than three significant figures.
The standard nominal diameters expressed in mils and mm have been calculated in accordance with these rules and are given in wire gauge table for convenient reference. The standard nominal diameters expressed in mm have been calculated based on the indicated mil diameter value × 0.0254:
d, mm = d, mils * 0.0254
consequently:
d, mils = d, mm / 0.0254
If a diameter in inches is required, the formula is as follows:
d, inches = d, mils / 1000 = d, mm / 25.4
Standard Nominal Cross-Sectional Areas
Standard nominal cross-sectional areas in circular mils and square millimetres shall be calculated in accordance with the following equations:
Area, cmil = d2
Area, mm2 = d2 * 5.067 * 10-4
where:
d = diameter of the wire in mils as given in AWG chart.
Rules for Calculations Involving Resistivity
Standard nominal resistances and other values derived from the resistivity units shall be calculated from the standard wire diameters specified in AWG chart in accordance with the following equations:
D – resistance at 20°C, Ω/1000 ft = [ ρ/(d2 * δ) ] * 105.35 (Ohms Per 1,000 ft)
D – resistance at 20°C, Ω/lb = [ ρ/(δ2 * d4) ] * 0.30940 * 106 (Ohms Per Pound)
where:
d = diameter of the wire in mils as given in AWG chart,
ρ = resistivity of the wire material at 20°C in Ω·lb/mile2 as given in Table 1, and
δ = density of the wire material at 20°C in g/cm3 as given in Table 1.
If you need to calculate resistance in Ω/km then use the formula:
D (resistance at 20°C, Ω/km) = D (resistance at 20°C, Ω/1000 ft) * 3.28084
| Material | Density, δ, at 20°C, g/cm3 | Resistivity , ρ, at 20°C, Ω· lb/mile2 |
|---|---|---|
| Copper (Volume Conductivity, % IACS: 100) | 8.89 | 875.20 |
| Copper (Volume Conductivity, % IACS: 97.66) | 8.89 | 896.15 |
| Copper (Volume Conductivity, % IACS: 97.16) | 8.89 | 900.77 |
| Copper (Volume Conductivity, % IACS: 96.66) | 8.89 | 905.44 |
| Aluminum, 1350 (Volume Conductivity, % IACS: 61.8) | 2.705 | 430.91 |
| Galvanized Steel, Class A Coating: Grade EBB (Non-Copper Bearing) | 7.78 | 5000 |
| Bronze: Class A | 8.89 | 2188 |
Rules for Calculations Involving Mass and Length
Standard nominal mass and lengths shall be calculated from the standard wire diameters specified in AWG chart, in accordance with the following equations:
W = d2 * δ * 0.34049 * 10-3
L = (1/d2) * (1/δ) * 2.9369 *106
where:
W = mass, lb/1000 ft,
d = diameter of the wire in mils as given in AWG chart,
δ = density of the wire material at 20°C in g/cm3 as given in Table 1, and
L = length, ft/lb.
