Created By : Rina Nayak

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 28, 2023

Gibbs Free Energy Calculator is a free online application that calculates the energy of a chemical process. The online Gibbs free energy calculator tool speeds up the calculation and displays the Gibbs free energy in a matter of seconds.

Choose a Calculation
Change in Enthalpy:
Change in Entropy:
Change in Gibbs Free Energy:

Gibbs Free Energy

Gibbs energy is a term used to describe the amount of energy that exists in the universe. G is a combination of enthalpy and entropy, and it's used in equations. As long as two requirements are met, the sign in front of Gibbs free energy shows the chemical reaction's direction.

Check how the boiling temperature of water changes with height, for example. Depending on the results of the delta G calculation, you have two choices

  1. If ΔG > 0, the reaction is nonspontaneous, meaning it requires external energy to start. Heat, a photon, or any other form of external power can be used.
  2. If ΔG < 0G is equal to zero, the reaction is spontaneous and occurs without external energy. You don't need to do anything; the reaction's atoms will start it up independently.

Gibbs Free Energy Formula | Delta G Equation

Learn How to calculate Gibbs free energy (the Gibbs free energy equation) using the delta G formula by referring below i.e. ΔG = ΔH − T * ΔS

  • Where, ΔG denotes the change in Gibbs free energy
  • ΔH denotes the difference in enthalpy.
  • ΔS denotes the change in entropy, and
  • The temperature in Kelvin is denoted by the letter T

Enthalpy vs Entropy

Enthalpy, abbreviated as H, is a type of energy calculated by adding the internal points of molecules and the energy flow. On the other hand, entropy is a measure of a molecule's randomness, as indicated by the letter S. At all times, the system strives towards the lowest enthalpy and highest entropy.

Entropy is measured in J/K, while enthalpy is measured in J * mol-1. As a result, the Gibbs free energy equation can be used to calculate Gibbs free energy units. Simply said, these are units of energy, usually in the form of J.

Formulas Gibbs Free Energy Calculator Uses

This tool uses real-life examples to apply the formula. Three out of four variables are all you need to know: change in enthalpy (ΔH) entropy (ΔS), temperature (T), or Gibbs free energy (ΔS). Simply enter all of your data and watch the fourth number appear, as the formula may be read backwards or in any way.

Here are all of the formulas we utilise for completeness' sake

  • ΔG = ΔH − T * ΔS;
  • ΔH = ΔG + T * ΔS; and
  • ΔS = (ΔH − ΔG) / T

How to use Gibbs Free Energy Calculator?

The following are the steps on how to use the Gibbs Free Energy Calculator. They are as beneath

  • : In the input area, enter the enthalpy, the system's internal energy, and x for the unknown.
  • To calculate the energy, click the "Calculate x" button
  • Finally, in the output field, the Gibbs free energy will be presented.

FAQ’s on Gibbs Free Energy Calculator

1. Gibbs free energy is determined by what?

Pressure has a role in the Gibbs free energy equation. For processes with constant pressure and temperature, it is a useful criterion of spontaneity.

2. What effect does temperature have on Gibbs free energy?

When the temperature rises, the reaction's free energy (G) can either rise or fall. The entropy (S) change determines this. The Greek letter delta is used to indicate a change in a quantity. As a result, the numeric value of free energy grows as the temperature rises.


3.Is Gibbs free energy important in determining equilibrium?

Chemical change will tend to occur in whatever direction reduces the value of the Gibbs energy under constant temperature and pressure. G°, which also defines the equilibrium constant K, determines the composition of the mixture at equilibrium.

4. What role does Gibbs energy play in determining a process's feasibility?

We can look at entropy changes in the system and its surroundings to forecast the possibility of a chemical shift. We can conclude that the chemical change is viable if the sum of these two entropy changes is positive.