Percent Yield Calculator
Inputs
Enter actual and theoretical yields to calculate percent yield.
What is Percent Yield?
Percent yield measures the efficiency of a chemical reaction. It compares the amount of product you actually obtain (actual yield) to the maximum amount you could theoretically produce (theoretical yield) based on stoichiometry.
A 100% yield means you obtained the maximum possible product. In practice, yields are often less due to side reactions, incomplete reactions, or product loss during purification.
The Percent Yield Formula
% Yield = (Actual Yield / Theoretical Yield) × 100- Actual Yield = The amount of product obtained from the experiment
- Theoretical Yield = The calculated maximum product based on stoichiometry
Examples
Example 1: Synthesizing Salt
Theoretical yield = 58.5 g NaCl. Actual yield = 52 g.
- % Yield = (52 / 58.5) × 100 = 88.9%
Example 2: Low Yield Reaction
Theoretical = 25 g. Actual = 12 g.
- % Yield = (12 / 25) × 100 = 48% (Low yield)
Why is Percent Yield Less Than 100%?
- Side reactions: Reactants form unintended products
- Incomplete reactions: Not all reactants convert to product
- Product loss: During transfer, filtration, or purification
- Impure reagents: Starting materials may not be 100% pure
Frequently Asked Questions
Can percent yield exceed 100%?
Theoretically no, but experimentally it can happen due to impurities in the product or incomplete drying (water weight).
What is a good percent yield?
Generally, 90%+ is excellent, 70-89% is good. Industrial processes aim for high yields for cost efficiency.