online electronic calculator - Ohm's law and much more

Wire R thermal drift calculator

Online calculator for formulas used in electronic circuit design and electrical engineering.

Basic electric calculations:

Ohm's Law, Ohm's Law with power, DC power, AC real power, LC resonant frequency, Capacitor charging/discharging, Capacitive reactance, Capacitive current + reactive power, Capacitor energy, Capacitor Δ energy, RC discharging, Inductor square pulse, Inductive reactance, Inductive current + reactive power, Inductor energy, 2 parallel resistors, 3 parallel resistors, System bandwidth

Wire and winding calculations:

Diameter ↔ cross section ↔ AWG, Wire resistance, Wire weight, Current density, Wire R thermal drift

Calculate Wire R thermal drift: 100Ω, 20°C, Ω, 60°C, copper


This calculator can calculate the resistance change of a winding or wire, caused by a temperature change. It can also calculate the temperature of a conductor or winding based on its resistance, knowing the resistance at a reference temperature. This calculation is done based on the temperature coefficient of resistance (TCR), also known as alpha (α) of the wire/winding metal (copper, aluminium, iron or silver).

Enter 3 values to calculate the 4th:

Resistance 1: -0.1 +0.1 -1 +1 -10 +10 -100 +100
Temperature 1: -0.1 +0.1 -1 +1 -10 +10 -100 +100
Resistance 2: -0.1 +0.1 -1 +1 -10 +10 -100 +100
Temperature 2: -0.1 +0.1 -1 +1 -10 +10 -100 +100
Wire metal:   Copper    Aluminium    Iron    Silver
Output metric prefix:   Automatic    User-selected
  Temperature rise Δt: 40 °C,   R change: +15.71709233792 %

Wire materials:

Copper: the best conductor of all non-precious metals. Its chemical symbol is Cu. Typical conductivity of a copper wire is about 57 MS/m and the resistivity about 17.54 nΩ⋅m at 20 °C. Density: 8.96 g/cm³. Linear thermal expansion: 16.7um/(m⋅K). The temperature coefficient of resistance α of copper is 0.004264 at 0 °C, 0.003929 at 20 °C and 0.003643 at 40 °C.
Aluminium: cheaper and lighter than copper, good conductivity. Its chemical symbol is Al. Typical conductivity of an aluminium wire is about 35.5 MS/m and the resistivity about 28.2 nΩ⋅m at 20 °C. Density: 2.70 g/cm³. Linear thermal expansion: 23.1um/(m⋅K). The temperature coefficient of resistance α of aluminium is 0.004704 at 0 °C, 0.004299 at 20 °C and 0.003959 at 40 °C.
Iron: very cheap, works as both a conductor and a structural part. Its chemical symbol is Fe. Typical conductivity of iron is about 10.3 MS/m and the resistivity about 97.1 nΩ⋅m at 20 °C. Density: 7.874 g/cm³. Linear thermal expansion: 11.8um/(m⋅K). The temperature coefficient of resistance α of iron is 0.006398 at 0 °C, 0.005672 at 20 °C and 0.005094 at 40 °C.
Silver: The best conductor, resistant to corrosion, but very expensive. Its chemical symbol is Ag. Typical conductivity of silver is about 63 MS/m and the resistivity about 15.87 nΩ⋅m at 20 °C. Density: 10.49 g/cm³. Linear thermal expansion: 19um/(m⋅K). The temperature coefficient of resistance α of silver is 0.004136 at 0 °C, 0.00382 at 20 °C and 0.003549 at 40 °C.

The temperature coefficient of resistance formula says:

•If a copper wire has 100Ω (ohms) resistance at 20°C (degree Celsius), its resistance at 60°C (degree Celsius) will be 115.7170923379Ω (ohms).
•A winding made of copper (Cu) had 100Ω (ohms) resistance measured at 20°C (degree Celsius). If its resistance has changed to 115.7170923379Ω (ohms), the temperature has changed to 60°C (degree Celsius).
•If the ambient temperature is 20°C (degree Celsius) and the wire or winding temperature is 60°C (degree Celsius), the temperature rise Δt is 40°C (degree Celsius).
•If a copper wire changes its temperature from 20°C (degree Celsius) to 60°C (degree Celsius), its resistance increases by 15.71709233792 percent.



This is a simple online calculator for formulas used in electronic engineering and design.

This online calculator is for reference only. I do not guarantee it to work correctly. You use this at your own risk only.