Equilibrium Calculator
Calculate the equilibrium constant Keq.
About Equilibrium Calculator
Equilibrium for Equilibrium compares product and reactant concentrations raised to their stoichiometric coefficients; a constant above one favors products and below one favors reactants. The equilibrium constant predicts which side dominates without needing to know the reaction mechanism.
Formula
Equilibrium
Keq = [products]^coef / [reactants]^coef
- Keq
- Ratio of product to reactant concentrations at equilibrium
Worked example
With the default values below, Equilibrium Calculator returns Equilibrium Constant of 4.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Product concentrationminimum 0
- 2
- Reactant concentrationminimum 0
- 0.5
- Coefficient ratiominimum 0
- 1
Results
- Equilibrium Constant
- 4.000
- log10(Keq)
- 0.602
- Direction
- Products favored
Step by step
- 1Values used
- 2Equilibrium
- 3Equilibrium Constant= 4.000
- 4log10(Keq)= 0.602
- 5Direction= Products favored
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Equilibrium calculated?
Keq = [products]^coef / [reactants]^coef Equilibrium for Equilibrium compares product and reactant concentrations raised to their stoichiometric coefficients; a constant above one favors products and below one favors reactants.
Why does Equilibrium matter?
The equilibrium constant predicts which side dominates without needing to know the reaction mechanism.
What values do I need to enter?
This calculator takes 3 inputs: Product concentration, Reactant concentration, Coefficient ratio. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.