Percent yield calculator
Compare the product you actually made with the most you could have made. Solve for the percent yield, the actual yield or the theoretical yield.
yield = actual ÷ theoretical × 100%
Use the same unit, such as grams or moles, for the actual and the theoretical yield.
How to use the calculator
Enter the actual yield, the amount of product you collected, and the theoretical yield, the amount the balanced equation predicts from your limiting reactant. The calculator divides one by the other and multiplies by 100.
You can also solve backwards: enter a percent yield to find how much product to expect, or how much you would need to aim for.
Worked example
A reaction should give 10.0 g of product, but you collect 8.5 g. The percent yield is 8.5 ÷ 10.0 × 100 = 85%.
Why yields are below 100%
Some product is lost when it is filtered, transferred or purified, reactions may not finish, and side reactions can turn some reactant into other products. A yield above 100% usually means the product is still wet or impure.
FAQ
What is theoretical yield?
It is the largest amount of product a reaction can give, worked out from the balanced equation and the amount of the limiting reactant, assuming everything reacts and nothing is lost.
Can percent yield be more than 100%?
Not for a pure, dry product. A result above 100% usually means the product still contains water, solvent or impurities, or that a mass was measured wrongly.