Chemistry calculator
Stoichiometry Calculator
Apply a balanced equation’s coefficient ratio to a known amount in moles.
Target amount
1 mol
How the stoichiometry calculator works
First balance the reaction, then enter the coefficients belonging to the known and target substances. Coefficients are ratio numbers; they must be positive, while the known mole amount may be zero.
The deliberately narrow scope avoids pretending to balance or parse an equation. Convert masses to moles before using the ratio and convert the target moles back to mass afterward if needed.
Worked example
For 2H2 + O2 → 2H2O, 3.0 mol H2 with coefficients 2 for H2 and 2 for H2O gives 3.0×2÷2 = 3.0 mol H2O. For O2 to H2O, 1.5 mol×2÷1 = 3.0 mol H2O.
Assumptions and practical limits
The result assumes the entered known reactant determines production and the reaction proceeds completely. It does not identify a limiting reactant or apply percent yield.
Use coefficients from a correctly balanced equation. Subscripts inside chemical formulas are not stoichiometric coefficients.
Frequently asked questions
Can I enter grams?
No. Convert grams to moles first using molar mass.
Does this balance equations?
No. Enter coefficients from an equation you have already balanced.
What if more than one reactant is known?
Calculate possible product from each reactant; the smallest product amount identifies the limiting reactant.