Math & Science
Stoichiometry Calculator
Calculate quantities in chemical reactions
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
Frequently asked questions
How do I enter equations?
Use + for reactants/products, -> for yields: H2 + O2 -> H2O
What is limiting reactant?
The substance that runs out first, determining maximum product yield.
How is theoretical yield calculated?
From stoichiometry assuming 100% conversion of limiting reactant.
Related tools
About this tool
Inputs
- Chemical Equation
- Known Substance
- Known Amount
- Unit
- Required/Produced Amounts
Results
- Balanced Equation
- Required/Produced Amounts
- Limiting Reactant
You do not need a spreadsheet to calculate quantities in chemical reactions. This Stoichiometry Calculator gives you the answer in seconds. Enter chemical equation, known substance, known amount, unit and required/produced amounts. The tool processes your data and returns balanced equation, required/produced amounts and limiting reactant. Many practical problems — from engineering to daily budgets — reduce to straightforward arithmetic once you identify the right formula.
Having a dedicated tool to calculate quantities in chemical reactions saves time you would otherwise spend searching for formulas or setting up a spreadsheet. The substance that runs out first, determining maximum product yield. Rounding to the appropriate number of significant figures avoids false precision. Compare multiple scenarios by saving or noting each result before changing inputs. Mathematical precision depends on the number of significant figures — more digits mean less rounding error.