Hess law calculator
Sum enthalpy steps with multipliers (reverse a step with −1, double it with 2, …).
Calculator
How to use
Hess's law
$$\Delta H_{\text{net}} = \sum m_i \Delta H_i$$
When to use
- Building an unknown reaction enthalpy from known steps.
Educational use only. Double-check values for labs, homework, and exams.