Chemistry
Kp Calculator
Calculate the pressure equilibrium constant from partial pressures, or convert Kc into Kp.
Your inputs
Change any value to update the result instantly.
Kp
0.5208
Change in gas moles (Δn)
-2
Kp from partial pressures
0.5208
Kp converted from Kc
1.4761 x 10^-4
Relationship
Kp = Kc × (RT)^-2
Only gases appear in Kp. Pressures here are in bar with R = 0.083145 L·bar/(mol·K); using atm requires R = 0.082057 instead.
What this calculator does
Calculates the pressure equilibrium constant Kp from partial pressures, or converts Kc into Kp at a given temperature.
What your result means
Kp describes a gas-phase equilibrium in pressure terms; when the number of gas moles does not change, Kp equals Kc.
Formula and working
Kp = (P_C^c × P_D^d) ÷ (P_A^a × P_B^b) ; Kp = Kc(RT)^Δn
- 1
Collect the inputs
What do you have? = 1; P(A) = 0.4 bar; Coefficient a = 1; P(B) = 1.2 bar; Coefficient b = 3; P(C) = 0.6 bar; Coefficient c = 2; Kc (for the conversion) = 0.5; Temperature = 700 K
- 2
Apply the formula
Kp = (P_C^c × P_D^d) ÷ (P_A^a × P_B^b) ; Kp = Kc(RT)^Δn
- 3
Result
Kp = 0.5208
Frequently asked questions
Symbols and assumptions
- Kp
- Equilibrium constant in pressure terms
- delta n
- Gas moles of products minus gas moles of reactants
- R, T
- Gas constant and absolute temperature
- • Gases behave ideally.
- • Pressures are in bar with R = 0.083145 L bar per mol per K.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • Only gaseous species appear. Using atm requires R = 0.082057 instead, which changes the conversion.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Report a mistake or request an improvement
Tell us if a formula, unit, explanation, or result needs attention. Your message will include this calculator’s name and page.
Related calculators
Equilibrium Constant (Kc) Calculator
Calculate Kc for aA + bB ⇌ cC + dD from the equilibrium concentrations.
Actual Yield Calculator
Find the mass of product you should expect to collect from a known percent yield.
Chemical Equation Balancer
Balance any chemical equation by conserving every element, with whole-number coefficients.
Molar Ratio Calculator
Convert moles of one substance into moles of another using the balanced equation coefficients.
Rate Constant Calculator
Find the rate constant k from a measured rate and reactant concentrations, with the correct units.
Activity Coefficient Calculator
Estimate the activity coefficient of an ion in a dilute solution using the Debye-Hückel limiting law.