Percent Yield Calculator
Use our percent yield calculator to calculate percent yield (%) from actual yield and theoretical yield. Includes the percent yield formula used in chemistry, step-by-step instructions, and guidance on what is a good percent yield.
What Is Percent Yield?
Percent yield measures how much product you actually obtained from a reaction compared to how much you could theoretically obtain based on stoichiometry.
In chemistry, theoretical yield is the maximum possible product amount assuming the reaction goes perfectly and nothing is lost. Actual yield is what you measured in the lab after running the reaction and isolating the product.
Percent yield is useful for comparing reaction efficiency, troubleshooting lab losses, and evaluating how well a procedure worked.
Percent Yield Formula
To calculate percent yield, divide the actual yield by the theoretical yield and multiply by 100.
Use the same units for both yields (for this calculator, grams).
An 84% yield means you obtained 84% of the maximum possible product.
How to Calculate Percent Yield
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Enter the actual yield (g).
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Enter the theoretical yield (g).
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The calculator applies (Actual ÷ Theoretical) × 100 to return percent yield (%).
Frequently Asked Questions
Percent yield = (actual yield ÷ theoretical yield) × 100. Actual yield comes from your lab result, and theoretical yield comes from stoichiometric calculations.
Use grams for both actual and theoretical yield, then apply the percent yield formula. Units cancel as long as they match.
It depends on the reaction and lab conditions. Some reactions routinely give high yields, while others are lower due to equilibrium limits, side reactions, or product loss during purification.
Percent yield compares product obtained to the theoretical maximum from a reaction. Percent recovery usually refers to how much of a known material you recovered after a process like purification or separation.
Common reasons include incomplete reaction, side reactions, product loss during transfers/filtration, or losses during purification.