Stoichiometry Calculator Online
Limiting reactants, theoretical yield, percent yield & more
Limiting Reactant
Theoretical Yield
Percent Yield
Mass-Mole
📐 Key Stoichiometry Formulas
Moles = Mass (g) / Molar Mass (g/mol)
Mass = Moles × Molar Mass
Percent Yield = (Actual / Theoretical) × 100%
Mole Ratio: n₁/coef₁ = n₂/coef₂
Limiting: smallest (moles / coefficient)
Quick Guide
Limiting Reactant
The reactant that runs out first, limiting how much product can form. Found by comparing moles/coefficient ratios.
Theoretical Yield
Maximum product possible from limiting reactant. Calculated using mole ratios from balanced equation.
Percent Yield
Compares actual to theoretical: (actual/theoretical) × 100%. Values under 100% are normal due to losses.
Mass-Mole Conversions
Use molar mass to convert: moles = mass/MM, mass = moles × MM.
FAQ
What is the limiting reactant?
The substance completely consumed first, limiting product formation. Other reactants are "in excess."
How to find theoretical yield?
Use moles of limiting reactant × mole ratio × product molar mass.
Why is percent yield over 100%?
Usually indicates error, impurities, or incomplete drying. Pure products can't exceed 100%.
How to balance equations?
Adjust coefficients so atoms are equal on both sides. Start with complex molecules.
Is this calculator free?
Yes, completely free with no limitations.