Percent Yield Calculator
Calculate actual, theoretical, or percent yield.
Enter any two of actual yield, theoretical yield, and percent yield to solve for the third. Use the same mass unit for both yields — the ratio cancels units, so grams with grams or moles with moles both work.
Theoretical yield always comes from the limiting reagent. Use the limiting reagent calculator first if you are not sure which reactant runs out.
How to Use the Percent Yield Calculator
1
Choose the unknown. Select whether you are solving for percent yield, theoretical yield, or the expected actual yield.
2
Enter the two known values. Type the two quantities you have, using the same unit for both yields.
3
Interpret the result. Read the percentage along with how much product was lost and whether the yield is typical for a preparative reaction.
What is the Percent Yield Calculator?
The percent yield calculator relates actual yield, theoretical yield, and percent yield using % yield = (actual / theoretical) × 100. Enter any two values to solve for the third, whether you are grading your own lab results or back-calculating the expected mass of product.
Real reactions rarely give 100% yield because of side reactions, incomplete conversion, and transfer losses. Percent yield quantifies that gap, and reporting it is a standard requirement in almost every chemistry lab course.
Common Uses
- Calculate percent yield from lab results
- Find theoretical yield from a known percent yield
- Estimate expected product mass before an experiment
- Compare efficiency across reaction conditions
How to Solve It by Hand
Manual calculation is still important: identify the known variables, convert units before substitution, apply the equation, and check whether the result is chemically reasonable. The most common mistakes are inconsistent units, constants rounded too early, and skipping the interpretation step.
Practice Prompt
Try changing the default values and ask the lower-right chemistry chat why the result increased or decreased. That turns the calculator from a number machine into a study loop.
Percent yield = (actual yield / theoretical yield) × 100. Actual yield is what you isolated and weighed; theoretical yield is the maximum the limiting reagent allows.
Almost always because the product is still wet with solvent or contains unreacted starting material, or because the theoretical yield was calculated from the wrong limiting reagent. Dry the sample to constant mass and recheck which reactant limits the reaction.
It depends on the reaction. Above 90 percent is excellent, 70 to 90 percent is good for a multi-step organic synthesis, and yields under 40 percent usually point to a procedural problem, a competing side reaction, or heavy losses during transfer and purification.
Yes, but the unit itself cancels. Grams with grams or moles with moles both give the same percentage; mixing grams with moles does not.
Yes. Switch to theoretical yield mode and enter the actual yield with the percent yield; the tool divides to recover the maximum possible mass.