Reaction Yield Calculator
Measure the efficiency of a reaction as percent yield from the actual and theoretical product masses.
How it works
percent yield = (actual yield ÷ theoretical yield) × 100
Reaction (percent) yield states how much product you actually isolated as a fraction of the maximum the stoichiometry allows. Real syntheses fall short of 100% because of side reactions, incomplete conversion and losses during transfer and purification. A figure above 100% is not real efficiency — it points to residual solvent or impurities in the weighed product.
Worked example
A preparation with a theoretical yield of 5 g that delivers 4.2 g of dried product has a yield of (4.2 ÷ 5) × 100 = 84%.
Sources: Yield (chemistry) — Wikipedia
Frequently asked questions
Where does the theoretical yield come from?
From the limiting reactant and the balanced equation: convert its moles to moles of product using the mole ratio, then to grams using the product molar mass. The theoretical yield calculator does this end to end.
Is a higher yield always better?
Usually, but purity matters too. A slightly lower yield of clean product often beats a high yield contaminated with by-products that then need extra purification.
Can yield exceed 100%?
Genuinely, no. A value over 100% means the product was not fully dried or still contains impurities, or there was a measurement slip. Dry, purify and reweigh.
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