Skip to main content
Calcimator

Equilibrium Constant Calculator

Calculate the equilibrium constant (Keq) from product and reactant concentrations with stoichiometric coefficients. Includes Gibbs free energy.

Inputs

M
M
M
M

Results

Equilibrium Constant (Keq)

2.5

log₁₀(Keq)0.398
ΔG° at T-2.27 kJ/mol
Equilibrium PositionProduct-favored
How to Use This Calculator
  1. Enter product concentrations and coefficients, then reactant concentrations and coefficients.
  2. Review the equilibrium constant K (Kc) for the reaction.
  3. K >> 1 means products are favored at equilibrium; K << 1 means reactants are favored.

How the result changes with Reactant 1 Coefficient

Reactant 1 CoefficientEquilibrium Constant (Keq)
1.910.6417
4.15397.8282
6.8530,684.1809
9.11,147,100

What each input means

Product 1 Concentration
Equilibrium concentration of the first product
Product 1 Coefficient
Stoichiometric coefficient of product 1 in the balanced equation
Product 2 Concentration
Equilibrium concentration of the second product (leave coefficient 0 if unused)
Product 2 Coefficient
Stoichiometric coefficient of product 2 (set to 0 if only one product)
Reactant 1 Concentration
Equilibrium concentration of the first reactant
Reactant 1 Coefficient
Stoichiometric coefficient of reactant 1 in the balanced equation
Reactant 2 Concentration
Equilibrium concentration of the second reactant (leave coefficient 0 if unused)
Reactant 2 Coefficient
Stoichiometric coefficient of reactant 2 (set to 0 if only one reactant)
Temperature
Temperature for Gibbs free energy calculation

How this is calculated

Formula

Keq = [Products]^coef / [Reactants]^coef

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Product 1 Concentration = 0.5, Product 1 Coefficient = 1, Product 2 Concentration = 0.5, Product 2 Coefficient = 0 = 9 input(s) provided
  2. Calculate Equilibrium Constant
    2.5 = 2.5
  3. Calculate log₁₀
    log₁₀
    0.398 = 0.398
  4. Calculate ΔG° at T
    ΔG° at T
    -2.27 = -2.27

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Chemistry

Reaction Rate Calculator

Calculate reaction rate from rate constant, reactant concentrations, and reaction orders using the rate law equation.

Chemistry

Electrochemistry Cell Potential

Calculate electrochemical cell potential using standard reduction potentials and the Nernst equation. Includes Gibbs free energy and equilibrium constant.

Chemistry

Molarity Calculator

Calculate the molarity (molar concentration) of a solution from solute mass, molar mass, and solution volume. Essential for chemistry lab work and solution preparation.

More in Science & Physics.