What This Calculator Does
This calculator finds the percent yield of a chemical reaction, which tells you how efficiently a reaction converted starting materials into the desired product compared to the maximum amount predicted by theory.
The Formula
Percent yield is calculated as Percent Yield = (Actual Yield ÷ Theoretical Yield) × 100. The actual yield is the mass of product you actually recovered from the reaction, and the theoretical yield is the maximum mass predicted by stoichiometry, assuming the reaction goes to completion with no losses.
A Few Notes
- Real reactions almost always give a percent yield below 100% due to side reactions, incomplete reactions, or product lost during purification.
- Both values should use the same mass unit (typically grams) for the result to be meaningful.
- This tool is intended for general educational and laboratory-planning purposes.
Last reviewed August 2026