AWG Wire Resistance Calculator
Use this AWG wire resistance workflow when you need a transparent resistance estimate from AWG size, conductor material, temperature, length, and conductor count.
- Estimated AWG diameter
- mil
- Estimated circular mil area
- cmil
- Adjusted resistance
- ohm/1000 ft
- Resistance at 20 C
- ohm/1000 ft
- Circuit resistance
- ohm
Calculation details
- Temperature factor
- x
- Calculation basis
- Selection boundary
Recent results
Formulas
- Diameter inches = 0.005 x 92^((36 - AWG) / 39)
- Diameter mils = diameter inches x 1000
- Circular mils = diameter mils^2
- Resistance at 20 C = material K x 1000 / circular mils
- Adjusted resistance = resistance at 20 C x (1 + alpha x (temperature C - 20))
- Circuit resistance = adjusted resistance x one-way length x conductor count / 1000
Use this calculator
Estimate AWG diameter, circular mil area, resistance per 1000 ft, and circuit resistance from material, temperature, and length.
Read the result
Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.
Check before final work
This is a wire-resistance estimate, not an ampacity, voltage-drop approval, conductor-selection, or code-compliance result. Verify manufacturer data and project conditions.
FAQs
Does this replace a conductor table?
No. It estimates resistance from AWG geometry and material constants. Use verified manufacturer or code-table values when a project requires them.
Why does temperature change resistance?
Metal resistance changes with conductor temperature. The calculator applies a simple linear temperature factor around the 20 C basis.
Can this select wire size for me?
No. This page only estimates resistance. Use sizing, ampacity, voltage-drop, and code checks separately.