Actual vs Theoretical Yield Calculator
Compare the mass you actually recovered against the theoretical maximum to get the percent yield of a reaction, plus the mass lost.
How it works
% yield = ( actual yield / theoretical yield ) × 100
Percent yield tells you how close a real reaction came to its ideal outcome. The theoretical yield is the maximum product predicted by stoichiometry when the limiting reagent is fully converted; the actual yield is what you weigh after isolating and purifying the product. Their ratio, as a percentage, captures losses from incomplete reactions, side reactions, and material left behind during transfer and purification.
Worked example
A synthesis has a theoretical yield of 10.0 g but you isolate only 8.5 g of purified product. Percent yield = (8.5 / 10.0) × 100 = 85 %, meaning 1.5 g was lost to side reactions and handling.
Sources: Yield (chemistry) — Wikipedia
Frequently asked questions
Can percent yield exceed 100 %?
Not for pure product. A value above 100 % almost always means the sample is still wet with solvent or contaminated with an impurity or unreacted starting material, inflating the mass.
Why is the actual yield almost always lower than theoretical?
Real reactions rarely go to completion, competing side reactions consume some reactant, and product is inevitably lost during filtration, transfer and recrystallisation. All of these pull the actual yield below the ideal.
How do I get the theoretical yield?
Find the limiting reagent, convert its moles through the balanced equation to moles of product, then multiply by the product’s molar mass. A limiting-reagent or theoretical-yield calculator does this directly.
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This calculator is for educational purposes. Double-check important results before acting on them.