Stoichiometry and limiting reactant calculator

Compute the limiting reactant, theoretical yield, remaining amounts, and percent yield from a balanced chemical equation.

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

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.

An example (2 H2 + O2 → 2 H2O) is preloaded and calculated automatically. Editing the inputs updates the form and the results card 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 is calculated

    FAQ

    What is a limiting reactant?

    The limiting reactant is the substance that is consumed first when the reaction goes to completion. It caps how much product can be formed and determines 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?

    Typical problems give masses, which you convert to moles using molar mass. This tool accepts either mass or moles, but a molar mass is required whenever a mass-to-mole conversion is needed.

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