Percent Yield Calculator
Compute percent yield from actual and theoretical yields. Both yields must use the same unit (grams or moles). Formula: % yield = (actual / theoretical) × 100.
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How to calculate percent yield
- Enter the actual yield you isolated or measured.
- Enter the theoretical yield from stoichiometry in the same unit.
- Read percent yield and the two inputs echoed for checking.
- Values above 100% usually signal impure product, a weighing error, or a wrong theoretical mass.
Percent yield
Reaction efficiency as a percent of theoretical product
| Actual yield | Mass or moles obtained experimentally |
|---|---|
| Theoretical yield | Mass or moles predicted by stoichiometry |
| Formula | % yield = (actual / theoretical) × 100 |
| Limiting reagent | Sets the theoretical yield before this page runs |
| Unit rule | Actual and theoretical must share grams or moles |
| Over 100% | Often impurity or calculation error, not true efficiency |
What percent yield measures
Percent yield compares what you recovered to what stoichiometry said was possible. 8.5 g actual from 10 g theoretical is 85% yield.
Actual yield, theoretical yield, and limiting reagent
Theoretical yield comes from the balanced equation and the limiting reagent. Actual yield is what you weigh after workup. This page does not solve stoichiometry; it only divides the two yields you supply.
How the percent is formed
The engine divides actual by theoretical and multiplies by 100. Theoretical yield must be greater than zero. Actual yield cannot be negative.
Limits
Informational arithmetic. Not a lab notebook substitute and not purity analysis. See the disclaimer.