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Chemistry

Van’t Hoff Equation Calculator

Estimate how an equilibrium constant changes between two temperatures for a stated reaction enthalpy.

Explicit units and model assumptionsLocal calculations with worked examples
Chemistry workspace
Chemistry workspace

Check the units, concentration basis and assumptions before interpreting the result.

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Your chemistry result

Your result

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Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter initial equilibrium constant, reaction enthalpy, initial temperature, final temperature.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

ln(K2/K1) = −ΔH/R × (1/T2 − 1/T1), with ΔH converted from kJ/mol to J/mol.

A WORKED EXAMPLE

Using initial equilibrium constant = 1, reaction enthalpy = 50 kJ/mol, initial temperature = 298.15 K, final temperature = 310 K, the result is 2.1619397. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

No. In this model heating increases K for an endothermic reaction (positive ΔH), and decreases K for an exothermic reaction (negative ΔH).

What to keep in mind

Assumes constant reaction enthalpy across the interval and dimensionless, consistently defined equilibrium constants. Educational calculation only; use validated procedures for laboratory work.

Reference: OpenStax Chemistry 2e — chemical quantities and models

Common questions

Does heating always increase the equilibrium constant?

No. In this model heating increases K for an endothermic reaction (positive ΔH), and decreases K for an exothermic reaction (negative ΔH).

Are my inputs uploaded?

No. This calculation runs in your browser without an account or an external API.

Methodology maintained by ClarityKit. How these tools are built and checked.