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) 

To calculate the thermal voltage, multiply the temperature by Boltzman’s constant, then divide by the charge.

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)