Enter the temperature (K), the Boltzman’s constant (1.38 * 10^-23), and the charge (coulombs) into the calculator to determine the Thermal Voltage. 

Thermal Voltage Formula

The following formula is used to calculate the Thermal Voltage.

Vth = k * T / q

  • Where Vth is the Thermal Voltage (volts)
  • T is the temperature (K) 
  • k is the Boltzman’s constant (1.38 * 10^-23) 
  • q is the charge (coulombs) 

How to Calculate Thermal Voltage?

The following example problems outline how to calculate Thermal Voltage.

Example Problem #1

  1. First, determine the temperature (K). In this example, the temperature (K) is determined to be 14 .
  2. Next, determine the Boltzman’s constant (1.38 * 10^-23)..
  3. Next, determine the charge (coulombs). In this case, the charge (coulombs) is found to be 7.
  4. Finally, calculate the Thermal Voltage using the formula above: 

Vth = k * T / q

Inserting the values from above and solving the equation yields: 

Vth = 14 * 1.38*10^-23 / 7 = 2.76e-23 (volts)


Example Problem #2

Using the same method as above, determine the variables required by the equation. For this example problem, these are:

temperature (K) = 9

Boltzman’s constant (1.38 * 10^-23)

charge (coulombs) = 2

Enter these given values into the calculator or above yields: 

Vth = 9 * 1.38*10^-23/ 2 = 6.21e-23 (volts)