Actual yield
Use the product amount actually isolated or measured.
Percent Yield Calculator (Chemistry)
Calculator Inputs
Theoretical yield
This usually comes from stoichiometry and the limiting reagent.
Percent yield
Chemistry formula: (actual ÷ theoretical) × 100.
Results
Summary
No calculation yet.
Key values
Actual yield—
Theoretical yield—
Percent yield—
Normalized comparison
| Quantity | Entered / solved value | Equivalent moles | Notes |
|---|---|---|---|
| Converted values will appear here. | |||
Notes
This page assumes actual yield and theoretical yield refer to the same product. It does not derive theoretical yield from a balanced reaction.
Formula and assumptions
Percent yield compares how much product you actually obtained with how much you should have obtained under ideal stoichiometric completion.
- Percent yield: % yield = (actual ÷ theoretical) × 100
- Actual yield: actual = theoretical × (% yield ÷ 100)
- Theoretical yield: theoretical = actual ÷ (% yield ÷ 100)
- Mass conversion: n = m / M where M is molar mass in g/mol
- Particles: n = particles / 6.02214076×10²³
- Gas volume: n = V / Vₘ using the selected ideal-gas molar volume
If you enter grams, milligrams, kilograms, or gas volume, the calculator needs a molar mass or a parseable chemical formula for the product. Percent yield above 100% can occur from impure product, retained solvent, weighing error, or an incorrect theoretical-yield estimate during experimental work.
Worked examples
Silver chloride precipitation: if the theoretical yield of AgCl is 14.34 g and you isolate 12.50 g, the percent yield is about 87.17%.
Water synthesis: if stoichiometry predicts 2.00 mol H₂O and you collect 1.84 mol, percent yield is 92.0%.
Solve for actual yield: if the theoretical yield is 10.0 g and the process gives 78%, the actual yield is 7.80 g.
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Frequently asked questions
Why might my percent yield be low?
Common causes include incomplete reaction, transfer losses, side reactions, filtration loss, or product left dissolved in solvent.
Why might percent yield be above 100%?
Usually because the collected product still contains solvent or impurities, or because the theoretical-yield estimate was too low. It is a useful warning flag, not a chemical impossibility theorem.
Can I mix grams and moles?
Yes. The calculator converts both yields to moles internally. For any mass-based entry, you need a molar mass.
Does this replace stoichiometry?
No. Stoichiometry gives the theoretical yield first. This page then compares that theoretical amount with your measured product.
Quick percent-yield facts
Percent yield uses one product basis
Actual and theoretical yield must refer to the same product species. Otherwise the ratio is chemically meaningless.
Same product
Theoretical yield is an upper limit
It comes from balanced-equation stoichiometry and the limiting reagent, assuming ideal conversion and collection.
Stoichiometry
Unit conversion does not change the chemistry
Grams, moles, particles, and ideal-gas volume can all represent the same amount of the same product once converted consistently.
Normalization
High percent yield is not always high purity
A large mass can still include impurities or trapped solvent, so percent yield and purity answer different questions.
Lab caution
Percent yield is a comparison, not a synthesis model
You still need stoichiometry or experiment to establish the theoretical amount first. Percent yield only compares that benchmark with what you actually recovered.
Interpretation