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Equilibrium Constant Calculator

Equilibrium constant calculator

Estimate equilibrium constant K from Gibbs free energy and temperature.

InputsChemistry2 fieldsLive

Result

K = 1.4873e+2

Uses ΔG° = -RT ln K.

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Advanced options
Flow
  • Enter standard Gibbs free energy in kJ/mol.
  • Enter temperature in Kelvin.
  • Read computed equilibrium constant K.
Example

Worked example: ΔG° = -12.4 kJ/mol at 298.15 K

  1. 1 Convert ΔG° to J/mol.
  2. 2 Compute exponent -ΔG°/(RT).
  3. 3 Apply exponential to get K.

K is approximately 148.5.

How
  1. Enter standard Gibbs free energy in kJ/mol.
  2. Enter temperature in Kelvin.
  3. Read computed equilibrium constant K.
Avoid
  • Using kJ/mol directly in exponent without J/mol conversion.
  • Entering Celsius temperature instead of Kelvin.
Checks

Best fit

Equilibrium Constant Calculator is built for estimate equilibrium constant k from standard gibbs free energy and temperature. If Equilibrium Constant Calculator does not match the input scope, compare the answer with a second method.

Input check

Match the entered values to this rule before copying the answer: ΔG° = -RT ln(K), so K = exp(-ΔG°/(RT)).

Sanity check

For Equilibrium Constant Calculator, use the worked example as a quick benchmark: K is approximately 148.5. If the equilibrium constant calculator answer is far away, check whether an input, unit, or mode changed.

Before copying

Review this common issue first: using kj/mol directly in exponent without j/mol conversion.

Ref only. Verify values. Follow lab safety.

FAQ
Can K be less than 1?

Yes. Positive ΔG° values produce K below 1.

Is this Kc or Kp?

It gives thermodynamic equilibrium constant form consistent with provided ΔG°.

Why does temperature matter?

The RT term scales the exponent and changes resulting K.

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