Percent Yield Calculator
The percent yield of a reaction: actual ÷ theoretical × 100.
Result
Percent yield (%)
80.00
How it works
Percent yield compares what a reaction actually produced with what it should have produced: actual ÷ theoretical × 100. Recover 8 g where the stoichiometry promised 10 g, and the yield is 80%. The theoretical yield comes from the balanced equation and the limiting reagent — the reactant that runs out first and therefore caps the product. Working it out means converting the limiting reagent to moles, applying the equation's ratio, and converting back to grams. A yield above 100% is not a triumph but a warning: it almost always means the product is still wet with solvent, or contaminated with unreacted starting material or a by-product. In industry the yield is watched closely because it is money — a process at 70% is throwing away nearly a third of its raw material.
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Frequently asked questions
Can yield exceed 100%?
Not really — values above 100% usually mean the product is impure or still wet.
What is theoretical yield?
The maximum product predicted by the balanced equation, assuming everything reacts perfectly.
What makes a yield fall short?
Reactions that stop before completion, competing side reactions, product lost on glassware or during filtration, and losses during purification. Each step of workup costs a few percent, which is why long syntheses end with low overall yields.
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