📈 Percent Yield Calculator
Enter actual and theoretical yield to get percent yield, or solve for the actual or theoretical value.
Percent yield
82 %
Percent yield = (actual yield ÷ theoretical yield) × 100. 🔒 Computed in your browser.
How the percent yield calculator works
Percent yield = (actual yield ÷ theoretical yield) × 100. Enter any two of the three and the tool solves for the third; actual and theoretical must be in the same units. Rearranged, actual = (percent yield ÷ 100) × theoretical, and theoretical = actual ÷ (percent yield ÷ 100), so you can back out whichever value you are missing.
Pairs with the stoichiometry calculator (which gives theoretical yield): divide your measured product by the theoretical maximum to see how efficient the reaction was.
Frequently asked questions
How do you calculate percent yield?
Divide the actual yield by the theoretical yield and multiply by 100. If you made 8.2 g and the theoretical maximum was 10 g, percent yield = 82%.
What is theoretical yield?
The maximum product the reaction could produce, from the limiting reagent, assuming no losses. Find it with the stoichiometry calculator.
Can percent yield exceed 100%?
Not really, a value above 100% usually means the product is impure or still wet (contains solvent or unreacted material), inflating the measured mass.
Why is actual yield less than theoretical?
Side reactions, incomplete reactions, and losses during transfer and purification all reduce the amount you actually recover.
What units should I use?
Any, as long as actual and theoretical are the same unit (both grams, or both moles).
If theoretical yield is 15 g and I recovered 12 g, what is my percent yield?
12 ÷ 15 × 100 = 80%. Enter 12 as actual and 15 as theoretical to confirm.
How do I get the expected actual yield for a target percent?
Multiply the theoretical yield by the fraction. For an 85% yield of a reaction with a 20 g theoretical maximum, expect 20 × 0.85 = 17 g.
Does percent yield measure purity?
Not directly. It measures how much product you recovered versus the maximum possible. A high yield of impure product is possible, which is why yields above 100% usually signal contamination or trapped solvent rather than a great reaction.
How does the limiting reagent affect percent yield?
The theoretical yield is always based on the limiting reagent, the reactant that runs out first. Using the wrong reactant (one in excess) to compute theoretical yield inflates it and makes the percent yield look artificially low.
Should I use moles or grams for percent yield?
Either works, as long as actual and theoretical are in the same unit, because percent yield is a ratio. Just be sure both refer to the same product, since the ratio cancels the units.