Percent Yield Calculator
Percent yield compares what a reaction actually produced with what the balanced equation says it should have produced. It is the standard measure of how well a synthesis went.
Percent yield
85.50%
- Mass short of theory
- -26.1
- Moles of product
- 1.8
- Yield before purity correction
- 90.00%
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
percent yield = actual mass / theoretical mass x 100
- actual
- The mass of product actually collected
- theoretical
- The mass the balanced equation predicts
- purity
- The fraction of the product that is the compound you want
How to check the result by hand
- 1
Work out the theoretical mass
Convert the limiting reagent to moles, apply the mole ratio from the balanced equation, and multiply by the molar mass of the product.
- 2
Weigh the dry product
Dry the product first, then weigh it. Residual solvent inflates the mass and pushes the apparent yield above the true value.
- 3
Correct for purity
If the crude product is not pure, multiply the weighed mass by the purity fraction. Ninety five percent purity leaves ninety five percent of the mass as useful product.
- 4
Divide and multiply by one hundred
162 grams divided by 180 grams is 0.9, and multiplying by one hundred gives a yield of 90 percent.
- 5
Sanity check the number
Anything above one hundred percent means an error somewhere, most often wet product or a wrong limiting reagent.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Percent Yield page.