ONE FORMULA, ONE ANSWER
Reaction equilibrium constant calculator
Calculate the dimensionless thermodynamic equilibrium constant from the standard reaction Gibbs energy for a specified reaction and standard state. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Activity-based equilibrium constant K
Enter values and select Calculate.
K = exp(−ΔᵣG°/(RT))
Assumptions
Required: standard molar reaction Gibbs energy at the entered temperature, matching the coefficients and direction of the written reaction. K is defined with dimensionless activities, rather than raw dimensional concentrations or pressures. Use temperature-specific Gibbs energy. Excluded: reaction rates, equilibration time and equilibrium composition.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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