Resistance Conversion Factors for Copper Wires

Temperature °C To reduce known RT to R20,
Multiply RTby
To convert R20 to RT,
multiply R20by
[Dynamic Content]



  • Conversion factors are base on Temp. Coefficient of Resistance of copper (α20)=0.00393
  • For any other temperatures out side the table range


R20=RT/1 + α20(T-20)
R=R20{1 + α20(T-20)}


R20 = Reference resistance at 20 deg C
T = Resistance at T deg C

T = Temperature at which measurement is made or to which reference Res. is required to be converted.

α 20 = Temperature Coefficient of resistance of copper conductor.