Percent Yield Calculator
Calculate the percent yield of a reaction from the actual and theoretical yields.
How it works
percent yield = (actual yield ÷ theoretical yield) × 100
Percent yield measures how efficient a reaction was: the mass you actually recovered as a fraction of the maximum the stoichiometry allows. Real reactions rarely reach 100% because of side reactions, incomplete conversion and losses during transfer and purification. A figure above 100% signals a contaminated or incompletely dried product rather than magic.
Worked example
If a reaction that should yield 10 g theoretically gives 8.5 g of product, the percent yield is (8.5 ÷ 10) × 100 = 85%.
Sources: Yield (chemistry) — Wikipedia
Frequently asked questions
How do I find the theoretical yield?
Work it out from the limiting reactant and the reaction stoichiometry — the theoretical yield calculator does exactly this from moles, mole ratio and product molar mass.
Can percent yield be more than 100%?
Not really. A value above 100% means the product still holds solvent or impurities, or was weighed incorrectly. Dry and purify, then reweigh.
What is a good percent yield?
It depends on the reaction. For many organic syntheses 70–90% is considered good; multi-step or difficult reactions may be much lower and still acceptable.
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