Equilibrium Constant Calculator (Kc/Kp)
Convert between the concentration-based equilibrium constant (Kc) and the pressure-based equilibrium constant (Kp) for a gas-phase reaction.
What is the relationship between Kc and Kp?
For gas-phase equilibria, the equilibrium constant can be expressed either in terms of molar concentrations (Kc) or partial pressures (Kp). The two are related by the equation Kp = Kc(RT)^Δn, where R is the gas constant, T is the absolute temperature, and Δn is the change in moles of gas between products and reactants.
How this calculator works
Choose whether you are converting Kc to Kp or Kp to Kc, then enter the known constant, Δn, and temperature in kelvin. The calculator computes the factor (RT)^Δn using R = 0.082057 L·atm/(mol·K) and applies it in the appropriate direction.
Note: Δn is calculated as (moles of gaseous products) − (moles of gaseous reactants); only gas-phase species count. This tool is intended for general chemistry education and planning purposes.