basic

Hess's Law Calculator (3 steps)

Sum step enthalpies (with optional reverse / multiply factors).

Add up to three step reactions with optional multipliers (use a negative coefficient to reverse a step) to compute the overall enthalpy change of a reaction by Hess's law.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

kJ/mol
kJ/mol
kJ/mol

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

ΔH_total = c₁·ΔH₁ + c₂·ΔH₂ + c₃·ΔH₃

In depth

Add up to three step reactions with optional multipliers (use a negative coefficient to reverse a step) to compute the overall enthalpy change of a reaction by Hess's law.