Percent Yield Calculator
Percent yield calculator: compare the actual mass of product with the theoretical yield, or find the theoretical yield needed.
η = mactualmtheoretical · 100 %
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
Percent yield is the actual mass of product you obtained divided by the theoretical maximum, times 100 %. The theoretical yield comes from stoichiometry and the limiting reagent.
Yields below 100 % reflect side reactions, incomplete reactions and losses during purification. A yield above 100 % usually means the product is still wet or impure.
Formula
η = mactualmtheoretical · 100 %
| Symbol | Quantity | Units |
|---|---|---|
| mact | Actual yield | kg, g, mg, µg, t, lb, oz, st, US ton, ct, Da |
| mth | Theoretical yield | kg, g, mg, µg, t, lb, oz, st, US ton, ct, Da |
| η | Percent yield | %, × |
Worked example
Given: mact = 8.5 g · mth = 10 g
η = mactmth
Result: η = 85 %
Frequently asked questions
How do I find the theoretical yield?
Convert the limiting reagent to moles, apply the mole ratio from the balanced equation, and convert the product moles back to grams with its molar mass.
Can percent yield exceed 100 %?
Not for a pure, dry product. Above 100 % points to solvent, water or impurities in the weighed sample.