Percentage Yield
The actual yield expressed as a percentage of the theoretical yield.
Formula / equation
% yield = (actual / theoretical) × 100
Unit
Dimensionless
In depth
Percentage yield measures the efficiency of a preparation and is a key figure of merit in industrial and pharmaceutical chemistry, where a multi-step synthesis multiplies each step's yield. A value above 100% signals an error — usually a wet or impure product rather than a violated conservation law.
Examples in the real world
Isolating 4.6 g from a possible 5.6 g gives a yield of 82%; a five-step synthesis at 80% each yields only 33% overall.