Percent Yield Calculator
Enter the actual and theoretical yield of a reaction to get the percent yield. You can also work backwards to find the actual or theoretical yield from a known percentage.
How to calculate percent yield
- Enter the actual yield you measured from the reaction.
- Enter the theoretical yield from your stoichiometry.
- Read the percent yield, computed as actual divided by theoretical times 100.
Examples
Standard percent yield
actual = 8 g, theoretical = 10 g
80%
Find theoretical yield
actual = 8 g at 80%
theoretical = 10 g
Frequently asked questions
What is percent yield?
Percent yield is the actual yield divided by the theoretical yield, times 100. It measures how efficient a reaction was in practice.
What is the percent yield formula?
Percent yield equals (actual yield / theoretical yield) x 100. Both yields must be in the same unit, such as grams or moles.
Can percent yield be over 100%?
Not really. A value above 100% almost always means the product was impure or still wet. This tool computes it but flags the result.
How do I find the theoretical yield?
Use the balanced equation and the limiting reactant to work out the maximum possible product, then convert to grams using molar mass.
Why is my yield low?
Common causes are side reactions, incomplete reactions, losses during transfer or purification, and an impure or excess starting material.
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