Calculate percent yield, actual yield, or theoretical yield for a reaction and compare recovery against the theoretical maximum.
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Science — Chemistry
A percent yield calculator compares the product you actually isolated with the reaction’s theoretical maximum. It can solve percent yield directly or work backwards to recover the actual yield or theoretical yield when the other two values are already known.
Percent yield measures how much product you recovered relative to the amount predicted by stoichiometry. It is one of the standard ways chemistry students and lab workers judge reaction efficiency and recovery.
Low values often reflect incomplete reaction, side reactions, or transfer and purification losses. Values above 100% usually indicate residual solvent, impurities, or an incorrect theoretical-yield assumption.
The standard expression compares actual yield with theoretical yield and converts the ratio into a percentage.
Percent yield = (actual yield / theoretical yield) × 100
Compares the isolated product against the theoretical maximum from stoichiometry.
Actual yield = (percent yield / 100) × theoretical yield
Back-solves the isolated product amount when percent yield and theoretical yield are known.
Suppose the theoretical yield is 50 g and the isolated product mass is 42.5 g. The percent yield is (42.5 / 50) × 100 = 85%.
That result indicates good recovery for a teaching-lab or bench-scale workflow, while still leaving room for expected purification and handling losses.
Frequently asked questions
Because the isolated material may contain solvent, water, impurities, filter-paper residue, or other non-product mass. A percent yield above 100% usually means the product was not fully dry or the theoretical-yield setup needs review.
Yes. Percent yield is a ratio, so the actual and theoretical values must refer to the same measurement basis. This page assumes you are comparing like with like.
No. High percent yield only shows the amount recovered relative to the theoretical maximum. Purity still requires separate analytical confirmation such as melting point, chromatography, spectroscopy, or another validated test.
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