Percent Yield Calculator
Calculate the percent yield of a chemical reaction from the actual yield and the theoretical yield to measure reaction efficiency.
Last reviewed by the Radiatus Cloud team
Calculate the percent yield of a chemical reaction.
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Calculate percent yield
Percent yield measures how efficient a chemical reaction is by comparing the amount of product actually obtained with the maximum amount predicted by theory. It is calculated by dividing the actual yield by the theoretical yield and multiplying by one hundred. The theoretical yield is the quantity of product that would form if the reaction proceeded perfectly with no losses, usually determined through stoichiometry. An actual yield of 8.2 grams against a theoretical 10 grams is an 82 percent yield.
A percent yield can range from zero up to one hundred percent, with higher values indicating a more efficient, cleaner reaction.
Why reactions fall short
Few reactions achieve a perfect hundred percent yield in practice. Product can be lost during transfer and purification, side reactions can consume reactants, reactions may not go to completion, and impurities can interfere. Percent yield quantifies these losses, which is why chemists report it to judge and compare the success of a procedure.
A yield above one hundred percent usually signals an error, such as a product that is still wet or contaminated, weighing more than it should. Both yields must be in the same units for a valid comparison. All calculation happens locally in your browser.
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Frequently Asked Questions
What is the percent yield formula?
Percent yield equals the actual yield divided by the theoretical yield, multiplied by one hundred.
What is theoretical yield?
It is the maximum amount of product a reaction could produce in theory, calculated from the balanced equation and the limiting reactant.
Why is yield rarely 100 percent?
Losses during transfer and purification, side reactions, incomplete reactions and impurities all reduce the amount of product obtained.
What does a yield over 100 percent mean?
It usually indicates an error, such as impure or wet product weighing more than the pure substance should.
What is a good percent yield?
It depends on the reaction, but yields above ninety percent are excellent, while complex syntheses may consider much lower yields acceptable.
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How to Use
Enter the actual yield and the theoretical yield.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.