Equilibrium Constant Calculator — Kc

The equilibrium constant is the signature ratio of products to reactants once a reaction settles. This single-product/single-reactant form covers the common textbook case — enter equilibrium concentrations and coefficients.

Equilibrium Constant Calculator — Kc

$K_c = \frac{[products]^p}{[reactants]^r}$

Solve for

Equilibrium [product] ([P])

Unit

Product coefficient (p)

Unit

Equilibrium [reactant] ([R])

Unit

Reactant coefficient (r)

Unit

Result unit

How to interpret the result

Worked check: N₂O₄ ⇌ 2NO₂ with [NO₂] = 0.020 M and [N₂O₄] = 0.10 M → Kc = 0.020²/0.10 = 0.0040. Kc > 1 favors products; Kc < 1 favors reactants.

Assumptions

Concentrations are true equilibrium values (not initial)
Activities approximated by molar concentrations
Single product and reactant terms