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Stoichiometry calculator (limiting reactant & percent yield)

From a balanced chemical equation, compute limiting reactant, theoretical yield, leftover amounts, and percent yield from moles or masses.

All calculations stay in your browser; no values are sent to any server.

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How to use (3 steps)

  1. Enter the balanced coefficients and labels for each reactant and the product.
  2. Provide each reactant as mass or moles plus molar mass when needed.
  3. Tap Compute and the Results card below will show the limiting reactant, theoretical yield, remaining amounts, and percent yield.

The page preloads and solves an example (2 H2 + O2 → 2 H2O). When you edit inputs, the form and results card update right away.

Inputs

Reaction setup

Reactant 1

Reactant 2

Product

Reactants

Reactant 1

g/mol
Given as

If you enter a mass, include the matching molar mass to convert it.

Reactant 2

g/mol
Given as

If you enter a mass, include the matching molar mass to convert it.

Product

g/mol
Actual yield (optional)

Enter an actual yield to calculate percent yield.

Results

Reaction
Limiting reactant
Theoretical yield of product
Percent yield

Reactant amounts

Product

If no actual yield is entered, the product’s actual columns and percent yield show “—”.

How it's calculated

    FAQ

    What is a limiting reactant?

    The reaction consumes the limiting reactant first as it goes to completion. This reactant caps product formation and sets the theoretical yield.

    Does this tool balance the equation for me?

    No. Balance the reaction first and enter the stoichiometric coefficients ν₁, ν₂, and νₚ. This calculator assumes the coefficients are already correct.

    Should I enter mass or moles?

    Most problems start with masses, then convert to moles using molar mass. This tool accepts mass or moles. Enter molar mass whenever you provide mass values.

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