What is the Reaction Stoichiometry Calculator?
Reaction stoichiometry converts a known amount of one reactant or product into moles and masses of every other species in a balanced equation. Enter an unbalanced or balanced equation, pick the known substance, and enter moles or grams. The tool auto-balances the equation, applies mole ratios from coefficients, and computes molar masses from chemical formulas. Runs instantly in your browser with no signup.
How to use the Reaction Stoichiometry Calculator
- Enter the chemical equation (use -> between reactants and products).
- Confirm the balanced equation preview.
- Select the known species and enter moles or mass in grams.
- Read moles and mass for all reactants and products in the table.
- Copy the summary for homework or lab reports.
Common use cases
- How much H₂O forms from 2 mol H₂ in H₂ + O₂ → H₂O
- CO₂ and H₂O masses from 16 g CH₄ combustion
- NH₃ yield in moles and grams from 28 g N₂
Frequently asked questions
- How does reaction stoichiometry work?
- nᵢ = n_known × (coefficientᵢ / coefficient_known). Mass follows from moles × molar mass for each species.
- Does the equation need to be balanced?
- No — the calculator balances it automatically before applying mole ratios.
- Can I start from product mass?
- Yes — select any species on either side and enter grams or moles.
- Does this find the limiting reactant?
- This tool assumes one known amount and scales all species proportionally. Limiting-reactant problems need amounts for multiple reactants compared separately.
