Percent Yield Calculator
Work out the percent yield of a reaction from the actual and theoretical yields — or rearrange to find either yield when you know the percentage.
Quick answer: Percent yield = (actual yield ÷ theoretical yield) × 100. If a reaction should make 8.0 g but you recover 6.5 g, percent yield = (6.5 ÷ 8.0) × 100 = 81.25%.
Percent yield compares how much product you actually obtained against the maximum the balanced equation predicts. It's a core measure of how efficient a reaction or synthesis was, and it's how lab reports quantify losses from side reactions, incomplete conversion and handling.
The formula
Percent yield = (actual yield ÷ theoretical yield) × 100
Actual = theoretical × percent ÷ 100 · Theoretical = actual × 100 ÷ percent
Actual = theoretical × percent ÷ 100 · Theoretical = actual × 100 ÷ percent
Worked example
A synthesis has a theoretical yield of 12.0 g and you isolate 9.6 g. Percent yield = (9.6 ÷ 12.0) × 100 = 80%.
Frequently asked questions
How do I calculate percent yield?
Divide the actual yield by the theoretical yield and multiply by 100.
What is theoretical yield?
The maximum product the balanced equation predicts from the limiting reactant, assuming perfect conversion.
Can percent yield be over 100%?
In principle no. A value above 100% usually means the product is impure or still wet with solvent.
Why is yield usually below 100%?
Side reactions, incomplete reactions, and losses during transfer and purification all reduce the amount recovered.
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