Gibbs Free Energy Calculator
🔥 Thermochemistry & Bonding. Use the Gibbs free energy formula to find δg, δh, temperature, δs: pick the value you want, type the others, and the answer updates as you go.
ΔG < 0 → the reaction goes by itself (spontaneous).
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| ΔG | kJ/mol |
| ΔH | kJ/mol |
| Temperature | K |
| ΔS | J/(mol·K) |
Worked example
Find the δg when ΔH = -92.2 kJ/mol, Temperature = 298 K, ΔS = -198.8 J/(mol·K).
Using Δ G = Δ H - TΔ S: ΔG = -32.958 kJ/mol.
Frequently asked questions
What is the formula for Gibbs free energy?
Δ G = Δ H - TΔ S. ΔG < 0 → the reaction goes by itself (spontaneous).
What do the letters stand for, and what units are used?
ΔG in kJ/mol, ΔH in kJ/mol, Temperature in K, ΔS in J/(mol·K).
How do you calculate δg?
Put the values into Δ G = Δ H - TΔ S. For example, with ΔH = -92.2 kJ/mol, Temperature = 298 K, ΔS = -198.8 J/(mol·K), δg = -32.958 kJ/mol.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (δg, δh, temperature, δs) and fill in the others: it rearranges the formula for you.
