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Stoichiometry and Limiting Reagent Calculator

Updated Sep 2026 Used 0 times
Use the positive balanced coefficient.
Use the positive balanced coefficient.
Use the positive balanced coefficient for the selected product.
Enter available amount after converting any mass with molar mass.
Enter available amount after converting any mass with molar mass.
Leave at zero when you only need theoretical yield.

Guest calculations stay on this device. Signed-in results sync privately.

Your result

Stoichiometry result

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.
Full calculation and sourcesAssumes the coefficients entered are already balanced for the stated reaction.

Versioned calculationFormula v1.0.0

Balanced-equation stoichiometryMole-ratio modelFormula v1.0.0
Public verification recordFormula v1.0.0
Review scope
Coefficient Ratios, Unit Normalization, Limiting Extent, Leftover Amounts, Yield Branch, And Boundaries
Review team
CalculatorGeek Algorithmic Team
Verified
2026-09-27
Next source review
2027-09-27
Automated fixtures
3 cases

Review method

Balanced H2/O2 reference, equivalent mmol inputs, zero-coefficient rejection, optional-yield behavior, and nonnegative leftovers reviewed separately.

Known limitations

  • The equation must already be balanced; the calculator does not parse or balance chemical formulas.
  • Theoretical yield assumes complete reaction with no competing reactions, loss, purity adjustment, or kinetic limitation.
  • Percent yield is shown only when a positive actual product amount is supplied and is not a statement of process quality.

Primary sources

On this page

Limiting-reagent method

For each reactant, divide available moles by its balanced coefficient. The smaller normalized amount is the reaction extent. Multiply that extent by the product coefficient to obtain theoretical product moles.

Percent yield

When an actual product amount is entered, percent yield = actual ÷ theoretical × 100. Keep actual and theoretical amounts in the same unit, and do not round the theoretical value early.

Common mistakes

  • Using unbalanced coefficients.
  • Comparing raw moles without dividing by coefficients.
  • Mixing grams and moles without a molar-mass conversion.
  • Treating theoretical yield as a guaranteed measured outcome.

Use the Molar Mass Calculator before entering mass-based data.

Frequently asked questions

Does this balance a chemical equation?

No. Enter coefficients from an already balanced equation.

Why can leftover moles be zero?

The limiting reactant is consumed at the theoretical endpoint; the other reactant may remain in excess.

Sources

From the guide library

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