About the Enthalpy Calculator

A free tool for finding reaction enthalpy via Hess's law.

What it is

This calculator sums the formation enthalpies of all reactants and products, weighted by their stoichiometric coefficients, and subtracts to find ฮ”Hยฐrxn โ€” then classifies the reaction as exothermic or endothermic.

Features

Any number of species

Enter as many reactants and products as your equation needs.

Exo/endothermic label

Instantly see which way heat flows.

Step-by-step

See the Hess's law sum spelled out.

Instant, private

Runs entirely in your browser. No data is sent anywhere.

Ready to use it?

Free, no sign-up required.

Open the Enthalpy Calculator