Percent Yield Calculator (Chemistry)

Percent yield compares what a chemical reaction (or any process with a known maximum possible output) actually produced against the maximum a perfect, loss-free run would produce: Percent Yield = (Actual Yield ÷ Theoretical Yield) × 100. The theoretical yield comes from stoichiometry — the limiting reagent's moles converted through the balanced equation's mole ratio into moles, then mass, of product — which this calculator doesn't compute; you supply it directly, since that conversion depends on the specific reaction's balanced equation.

Any mass unit works as long as the actual and theoretical figures use the same one, since the units cancel in the ratio — grams, milligrams, or kilograms all give an identical percentage.

A result below 100% is the normal case, reflecting real losses (incomplete reactions, side reactions, product lost during purification or transfer). A result above 100% is also possible and isn't flagged as an error here — it usually means the measured product still contains impurities, residual solvent, or moisture that's adding extra mass rather than the reaction somehow exceeding its true theoretical limit.