Percent Yield
Calculator
Results
- Percent yield (%)
- 85
- Mass not recovered (g)
- 1.5
Chemistry results
| Percent yield (%) | 85 |
| Mass not recovered (g) | 1.5 |
formula-map diagram
- Percent yield (%)
- 85
- Mass not recovered (g)
- 1.5
Formula breakdown
Formula
% yield = (actual ÷ theoretical) × 100= 85
Note
Simplified model: these results assume ideal behaviour (ideal gases, dilute solutions, complete reactions) and standard textbook constants. Real laboratory values vary with temperature, pressure, purity and activity coefficients. Do not rely on this for safety-critical or analytical work.
More in Chemistry
See all →Frequently asked questions
What is the difference between theoretical yield and actual yield?+
Theoretical yield is the maximum amount of product predicted by stoichiometry assuming the reaction goes to completion with no losses, while actual yield is what you actually measure in the lab. Percent yield compares the two: (actual / theoretical) x 100%.
Why is percent yield almost always below 100%?+
Real reactions lose product to side reactions, incomplete conversion, purification steps (like filtration or recrystallization), and material sticking to glassware, so some product is inevitably lost. A yield in the 70-90% range is often considered good for many organic syntheses.
Can percent yield ever exceed 100%?+
Yes, but it usually signals a problem such as impure product, residual solvent or water not fully removed, or an error in weighing rather than a genuinely more efficient reaction. A yield significantly over 100% should prompt you to check the purity and drying of your sample.
How do I calculate theoretical yield before I can find percent yield?+
Convert the limiting reactant's mass to moles, use the balanced equation's mole ratio to find moles of product, then convert those moles to grams using the product's molar mass. This theoretical yield in grams is the denominator in the percent yield formula.
Does the limiting reactant matter for this calculation?+
Yes, theoretical yield must always be based on the limiting reactant, since it's the reagent that runs out first and caps how much product can form. Using the reactant in excess instead will overstate the theoretical yield and understate percent yield.