Free Chemistry Calculator

Stoichiometry Calculator

Calculate the ideal amount of one reaction substance corresponding to a known amount of another. Enter formulas and coefficients from a balanced equation; this tool converts through the stoichiometric mole ratio.

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Convert one reaction amount to another

Use coefficients from a balanced chemical equation. This page models one known substance and one target, not competing limiting reagents.

Use the formula exactly as represented in the balanced equation.
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What is a stoichiometry calculator?

A stoichiometry calculator uses coefficients from a balanced reaction to relate amounts of two substances. It differs from the Chemical Equation Balancer, which finds coefficients, and from the Theoretical Yield Calculator, which compares several reactants to find a limiting reagent.

How does this stoichiometry calculator work?

The known amount is converted to moles using its formula when necessary. Moles are multiplied by target coefficient ÷ known coefficient, then converted to the selected target unit using target molar mass.

What formula does stoichiometric conversion use?

Target moles = known moles × (target coefficient ÷ known coefficient). For mass inputs or outputs, moles = grams ÷ molar mass and grams = moles × molar mass.

How do you use the stoichiometry calculator?

Balance the equation, copy the coefficient and formula for the known and target substances, enter the known amount, then choose units. Check each formula with the Molar Mass Calculator if hydration or grouped atoms are involved.

What do stoichiometry results mean?

The result is the ideal target amount implied by the entered mole ratio. It assumes the known amount reacts according to that equation. The intermediate moles can be checked with the Grams to Moles Calculator.

What does a two-substance stoichiometry result leave out?

It does not identify a limiting reagent, model percent conversion, purity, equilibrium, side reactions, or experimental loss. Use the Percentage Calculator only for a separate percent comparison, not as a substitute for chemical stoichiometry.

Who should use this reaction ratio calculator?

It is useful for textbook reaction conversions and preliminary reagent planning after an equation is balanced. Real laboratory work requires purity, concentration, safety, and process controls beyond this ideal calculation.

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Frequently asked questions about Stoichiometry

Stoichiometry describes quantitative relationships between substances that react and products that form in a specified reaction.
Yes. The coefficients must come from a correctly balanced equation.
Yes. The known formula is used to convert grams or milligrams to moles.
Yes. Choose grams, milligrams, moles, or millimoles as the primary target unit.
Molar masses are needed whenever a mass unit is converted to or from moles.
No. It models one known substance; use the Theoretical Yield Calculator to compare multiple reactants.
Any equivalent proportional coefficients give the same mole ratio, though smallest whole-number coefficients are standard.
No. It is an ideal stoichiometric conversion and does not model loss or incomplete reaction.

Sources and methodology

The calculation method and explanatory context can be checked against these authoritative primary references.

Scope: This free tool supports learning and planning. Confirm important laboratory, academic, medical, environmental, or industrial work with current protocols and qualified review.
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