Actual yield
The product measured or isolated after the reaction and recovery process.
Percent Yield Calculator — Actual and Theoretical Yield
Percent yield equals actual yield divided by theoretical yield, multiplied by one hundred.
Enter the two known values
Choose the value that is missing from your problem.
Theoretical yield
The maximum from balanced-equation stoichiometry and the limiting reactant.
Percent yield
Enter the known reaction yield as a percentage, not a decimal.
Advanced units and conversions
Choose the two units to see which conversion information is required.
Use a formula, not a common name. Both yields must refer to this same product.
Required for an ambiguous label or an unsupported formula.
Enter a formula or manual molar mass for confirmation.
Gas volume depends on temperature and pressure; choose the reference matching the problem.
Examples and result options
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Result
Percent yield
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Enter two values to calculate.
Key values
Actual yield—
Theoretical yield—
Yield loss amount—
Yield loss percentage—
Calculation steps
- Enter the two known values to see substituted working.
Notes
Actual and theoretical yield must describe the same product. Same-unit ratios do not require a formula or molar mass.
How to use the percent yield calculator
- Choose the missing value. Select percent yield, actual yield, or theoretical yield.
- Enter the two known values. For the default calculation, enter actual and theoretical yield.
- Select one shared unit. Values can be compared directly when they describe the same product in the same dimensional unit. Open Advanced units only when conversion is necessary.
- Read the result and working. The calculator updates automatically after valid input; the Calculate button provides an explicit action and moves focus to the result.
Percent yield formulas
Which formula should I use? Use the card for the missing value in your problem. Keep actual and theoretical yield on the same product basis before substituting.
Find percent yield
Percent yield equals actual yield divided by theoretical yield, multiplied by one hundred.- Y% = percent yield
- A = actual yield
- T = theoretical yield
Find actual yield
Actual yield equals theoretical yield multiplied by percent yield divided by one hundred.- A = actual yield
- T = theoretical yield
- Y% = percent yield
Find theoretical yield
Theoretical yield equals actual yield divided by percent yield divided by one hundred.- T = theoretical yield
- A = actual yield
- Y% = percent yield
Worked percent-yield solutions
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Calculate percent yield from a stoichiometric prediction
Given: a balanced-equation and limiting-reactant calculation predicts 14.34 g AgCl. The dry AgCl isolated in the laboratory is 12.50 g.
- Select the formula: Y% = (A ÷ T) × 100.
- Substitute: Y% = (12.50 g ÷ 14.34 g) × 100.
- Calculate: Y% = 0.871687… × 100 = 87.1687…%.
- Report: 87.17% to four significant figures.
Interpretation: 87.17% of the stoichiometric maximum was isolated. The 14.34 g theoretical yield came from stoichiometry; the percent-yield formula does not derive it from the reactants.
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Calculate actual yield
Given: theoretical yield = 10.0 g and percent yield = 78%.
- Select the formula: A = T × (Y% ÷ 100).
- Substitute: A = 10.0 g × (78 ÷ 100).
- Calculate: A = 10.0 g × 0.78 = 7.80 g.
- Report: 7.8 g to two significant figures, matching 78%.
Interpretation: the experiment would be expected to isolate about 7.8 g of product at a 78% yield.
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Calculate theoretical yield
Given: actual yield = 5.10 g and percent yield = 72.0%.
- Select the formula: T = A ÷ (Y% ÷ 100).
- Substitute: T = 5.10 g ÷ (72.0 ÷ 100).
- Calculate: T = 5.10 g ÷ 0.720 = 7.0833… g.
- Report: 7.08 g to three significant figures.
Interpretation: the stated actual yield is 72.0% of a 7.08 g theoretical maximum.
How to interpret percent yield
What the result can show
A yield below 100% says that less product was isolated than the ideal stoichiometric maximum. Reasons can include an incomplete reaction, equilibrium limits, competing reactions, transfer loss, product left in solution, or losses during filtration, washing, drying, and purification.
A reported yield above 100% is a prompt to check retained solvent, wet or impure product, balance and measurement error, product identity, and the limiting-reactant calculation.
What the result does not show
Percent yield is not purity: an impure solid can have a large measured mass. It is also not percent conversion (reactant consumed), selectivity (desired product relative to products formed), or atom economy (how reactant atoms appear in the desired product).
A yield should not be called “good” or “excellent” without a reaction-specific, method-specific, or discipline-specific benchmark.
Common mistakes
- Dividing theoretical yield by actual yield instead of actual by theoretical.
- Comparing different products or unmatched units.
- Entering a percentage as a decimal—for example, entering 0.78 when the field expects 78%.
- Treating theoretical yield as an experimental measurement instead of deriving it from the balanced equation and limiting reactant.
- Rounding intermediate values too early or reporting more significant figures than the inputs support.
Frequently asked questions
How do I calculate percent yield?
Divide the actual yield by the theoretical yield, then multiply by 100. Both values must describe the same product and must use the same unit or be converted to equivalent amounts first.
How do I find actual yield?
Multiply the theoretical yield by the percent yield written as a decimal: actual yield = theoretical yield × (percent yield ÷ 100).
How do I find theoretical yield?
Divide the actual yield by the percent yield written as a decimal: theoretical yield = actual yield ÷ (percent yield ÷ 100). The theoretical yield itself normally comes from balanced-equation stoichiometry and the limiting reactant.
Do actual and theoretical yield need the same units?
They must be directly comparable. Use the same dimensional unit for a simple ratio, or convert both amounts to an equivalent basis for the same product. A same-unit ratio does not need molar mass because the unit cancels.
Can percent yield exceed 100%?
A reported result can exceed 100%, but that usually points to retained solvent, wet or impure product, measurement error, or an underestimated theoretical yield. It does not mean the reaction produced more pure product than stoichiometry allows.
Is a 100% yield possible?
It is possible in principle and may be reported after rounding, but exactly 100% isolated yield is uncommon because reactions and product recovery usually involve some loss or uncertainty.
What does a low percent yield mean?
It means the isolated amount is small relative to the stoichiometric maximum. Possible causes include incomplete reaction, equilibrium, competing reactions, transfer loss, purification loss, or measurement error.
What is the difference between actual yield and theoretical yield?
Actual yield is the product measured or isolated in the laboratory. Theoretical yield is the maximum amount predicted from a balanced equation and the limiting reactant under ideal assumptions.
How many significant figures should percent yield have?
Keep extra digits during the calculation, then round the final result to the same number of significant figures as the least precise measured or calculated input, unless your course or laboratory protocol specifies another rule.
Can I calculate percent yield using volume?
Yes, when both volumes represent the same product under comparable conditions. For gas volumes at different units or when comparing volume with mass or amount, use the advanced conversion controls and state the gas molar-volume reference.
Editorial and chemistry review
Methodology: calculations use the standard relationship between actual yield and theoretical yield. Theoretical yield must first be established from a balanced chemical equation, stoichiometric mole ratios, and the limiting reactant. Advanced conversions normalize two quantities for the same product; they do not replace a limiting-reagent calculation.