Answer first
What this calculator tells you
Calculate the percent yield of a reaction from the actual and theoretical yield. Judge how efficient a synthesis or a batch process was against the maximum possible. Formula: Percent yield = actual yield ÷ theoretical yield × 100. At the worked-example inputs, the percent yield is 82.0%. Holding every other input steady, moving actual yield from 6.6 to 9.8 moves the result from 66.0% to 98.0%.
Transparent method
The formula
Judge how efficient a synthesis or a batch process was against the maximum possible.
Worked example
Example inputs
How to interpret the result
Percent yield compares what a reaction actually made with the most it could make on paper. An actual 8.2 grams out of a theoretical 10.0 is 82 percent, and the missing 1.8 grams went to side reactions, transfers and losses in purification. Yields near 100 percent are rare in real work. A yield above 100 percent is a warning that the product is wet or impure.
At the worked-example inputs the percent yield is 82.0%. It rises with actual yield and falls as theoretical yield increases.
These are exact physics and chemistry formulas. Real-world results add tolerances from component quality, temperature and measurement error that this calculator does not model.
Before you rely on it
What to check
Weigh the product dry and pure before you compute the yield. Solvent left in the sample inflates the actual figure.
The common error
Where people go wrong with percent yield calculator
Comparing an actual mass with a theoretical number of moles. Both must be in the same unit, and the theoretical yield comes from the limiting reagent.
Sensitivity evidence
How actual yield changes the percent yield
Holding every other input at the worked-example value, moving actual yield from 6.6 to 9.8 moves the percent yield from 66.0% to 98.0%: a spread of 32.0%, or 39% of the worked-example result.
| Actual yield | Percent yield | Amount lost |
|---|---|---|
| 6.6 | 66.0% | 3.4 |
| 7.4 | 74.0% | 2.6 |
| 8.2worked example | 82.0% | 1.8 |
| 9 | 90.0% | 1 |
| 9.8 | 98.0% | 0.2 |
Every input, tested
Which input moves the percent yield most
Of the 2 inputs, theoretical yield moves the percent yield most (16.6% across the range tested) and actual yield moves it least (16.0%).
| Input | Tested from | To | Percent yield at each end | Swing |
|---|---|---|---|---|
| Theoretical yield | 9 | 11 | 91.1% to 74.5% | 16.6% (20%) |
| Actual yield | 7.4 | 9 | 74.0% to 90.0% | 16.0% (20%) |
Two variables at once
Percent yield by actual yield and theoretical yield
Across the grid the percent yield runs from 55.0% to 122.5%. Moving actual yield from 6.6 to 9.8 shifts it by 32.0% at the middle column, and moving theoretical yield from 8 to 12 shifts it by 34.2% at the middle row, so theoretical yield is the bigger lever here.
| Actual yield \ Theoretical yield | 8 | 10 | 12 |
|---|---|---|---|
| 6.6 | 82.5% | 66.0% | 55.0% |
| 7.4 | 92.5% | 74.0% | 61.7% |
| 8.2 | 102.5% | 82.0% | 68.3% |
| 9 | 112.5% | 90.0% | 75.0% |
| 9.8 | 122.5% | 98.0% | 81.7% |
The highlighted cell is the worked example: 82.0%.
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Actual yield | 8.2 | Enter the actual yield used in this calculation. |
| Theoretical yield | 10 | In the same unit as the actual yield. |
| Percent yield | 82.0% | |
| Amount lost | 1.8 | |
Inputs, definitions and assumptions
Actual yield
Enter the actual yield used in this calculation. The prefilled worked-example value is 8.2.
Theoretical yield
In the same unit as the actual yield. The prefilled worked-example value is 10.
How to use this calculator
- 1Verify the inputs. Gather actual yield and theoretical yield from your own documents; the prefilled values are examples.
- 2Save a baseline. The worked example puts the percent yield at 82.0%. Store your own version of it as Scenario A.
- 3Test one change. Start with theoretical yield, the input with the biggest effect here: moving theoretical yield from 9 to 11 takes the percent yield from 91.1% to 74.5%, a swing of 20% of the worked-example figure.
- 4Check the extremes. At half the example theoretical yield (5) the percent yield is 164.0%; at double (20) it is 41.0%.
People also ask
Frequently asked questions
How do you calculate percent yield?
Percent yield = actual yield ÷ theoretical yield × 100. At the worked-example inputs the percent yield is 82.0%.
What does the percent yield result mean?
Judge how efficient a synthesis or a batch process was against the maximum possible. At the worked-example inputs the percent yield is 82.0%. It rises with actual yield and falls as theoretical yield increases.
How much does actual yield change the percent yield?
Holding every other input at the worked-example value, moving actual yield from 6.6 to 9.8 moves the percent yield from 66.0% to 98.0%, a spread of 32.0%.
What are the limits of this percent yield calculator?
These are exact physics and chemistry formulas. Real-world results add tolerances from component quality, temperature and measurement error that this calculator does not model. The tables on this page test actual yield only from 6.6 to 9.8; a value outside that range is not tabulated here.
Which input moves the percent yield most in the percent yield calculator?
Ranked by how far each moves the percent yield across the range tested: theoretical yield (16.6%, 20%) and actual yield (16.0%, 20%).
If I double theoretical yield in the percent yield calculator, does the percent yield double?
Doubling it from 10 to 20 takes the percent yield from 82.0% to 41.0%, which is 0.50 times the worked-example figure. So it falls instead of rising. Halving it to 5 gives 164.0%.
How much does theoretical yield matter in the percent yield calculator?
The worked example uses 10. Holding every other input at its worked-example value, moving theoretical yield from 9 to 11 takes the percent yield from 91.1% to 74.5%, a swing of 20% of the worked-example figure.
Which inputs change the amount lost in the percent yield calculator?
At the worked-example inputs it is 1.8. Actual yield takes it from 2.6 to 1 and theoretical yield takes it from 0.8 to 2.8.
What does specific gravity actually tell you?
How dense a substance is relative to water. A specific gravity above 1 means it's denser than water and will sink in it. Below 1 means it's less dense and will float. It's a quick, unit-independent way to compare materials.
Does molarity change if you heat a solution?
Yes, slightly: liquids expand as they warm, increasing the solution's volume without changing the amount of dissolved solute, which lowers the molarity. This is why precise chemistry work specifies the temperature a molarity was measured or prepared at.
Sources and evidence
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