Enter the temperature (K) and the equilibrium constant into the calculator to determine the Standard Free Energy. 

Standard Free Energy Formula

The following equation is used to calculate the Standard Free Energy. 

SFE = -R*T*ln(K)


  • Where SFE is the Standard Free Energy (Joules)
  • T is the temperature (K) 
  • K is the equilibrium constant 
  • R is the universal gas constant (8.3145 J/mol-K)

How to Calculate Standard Free Energy?

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

Example Problem #1:

  1. First, determine the temperature (K). In this example, the temperature (K) is measured to be 95.
  2. Next, determine the equilibrium constant. For this problem, the equilibrium constant is calculated to be 4.
  3. Finally, calculate the Standard Free Energy using the formula above: 

SFE = -R*T*ln(K)

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

SFE = -8.314*95*ln(4) = -1094.93 (Joules)

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: 

temperature (K) = 5

equilibrium constant = 3

Entering these values into the formula or calculator above gives us: 

SFE = -8.314*5*ln(3) = -45.669 (Joules)