Enter the forward activation energy (J) and the change in enthalpy (J/mol) into the calculator to determine the Reverse Activation Energy. 

Reverse Activation Energy Formula

The following equation is used to calculate the Reverse Activation Energy. 

RAE = FAE - dH


  • Where RAE is the Reverse Activity Energy (J)
  • FAE is the forward activation energy (J) 
  • dH is the change in enthalpy (J/mol) 

To calculate the reverse activity energy, subtract the change in enthalpy by the forward activation energy.

How to Calculate Reverse Activity Energy?

The following two example problems outline the steps and information needed in order to calculate the Reverse Activity Energy.

Example Problem #1:

  1. First, determine the forward activation energy (J). In this example, the forward activation energy (J) is measured to be 41.
  2. Next, determine the change in enthalpy (J/mol). For this problem, the change in enthalpy (J/mol) is calculated to be 3.
  3. Finally, calculate the Reverse Activation Energy using the formula above: 

RAE = FAE – dH

Inserting the values from above and solving the equation with the imputed values gives: 

RAE = 41 – 3= 38(J)

Example Problem #2: 

Using the same process as example problem 1, we first define the needed variables outlined by the formula. In this case, the values are provide as: 

forward activation energy (J) = 400

change in enthalpy (J/mol) = 24

Entering these values into the formula or calculator above gives us: RAE = 400 – 24 = 376 (J)