🏭Percent Yield Calculator
Enter any two values — actual yield, theoretical yield, percent yield — and leave the third blank to solve for it.
Free Percent Yield Calculator
Percent yield compares how much product a reaction actually produced against how much the balanced equation predicts. Our free percent yield calculator uses the formula %Yield = (Actual Yield ÷ Theoretical Yield) × 100, and it works in any direction — enter the actual and theoretical yield to find percent yield, or enter the percent yield with one of the yields to solve for the other.
This is the calculation used at the end of nearly every stoichiometry lab: after you calculate the theoretical yield from your limiting reagent, compare it against what you actually recovered. A low percent yield often points to side reactions, incomplete reactions, or losses during purification and transfer.
Runs entirely in your browser — free, no sign-up, no limits.
About the Percent Yield Calculator
Features
Solve for any value
Leave any one field blank — actual yield, theoretical yield, or percent yield — and the calculator solves for it.
Step-by-step working
See the exact formula and substitution used to reach the answer.
Unit-agnostic
Works with grams, milligrams, or moles — as long as both yields use the same unit.
Instant, private
Runs entirely in your browser. No data is sent anywhere.
Frequently Asked Questions
What is the formula for percent yield?
Percent yield = (Actual Yield ÷ Theoretical Yield) × 100. Actual yield is the amount of product you actually recover from an experiment; theoretical yield is the maximum amount predicted by the balanced equation and your limiting reagent.
Can percent yield be over 100%?
Yes, though it usually indicates an error rather than a real result. Common causes are impure product (unreacted starting material or solvent still weighed in), or a measurement mistake.
Why is percent yield usually less than 100%?
Side reactions, incomplete reactions, and product lost during transfer, filtration, or purification all reduce the actual yield below the theoretical maximum.
How do I find the theoretical yield?
Use stoichiometry: convert the limiting reagent's mass to moles, use the balanced equation's mole ratio to find moles of product, then convert to grams using the product's molar mass.
What units does this calculator use?
The tool is unit-agnostic for mass — enter actual and theoretical yield in the same unit (grams, milligrams, or moles) and the percent yield will be correct regardless of which unit you use.
Can this calculator find the actual yield from a target percent yield?
Yes. Leave the actual yield field blank, enter theoretical yield and the percent yield you want to hit, and the calculator solves for the actual yield.
Can it find the theoretical yield instead?
Yes. Leave the theoretical yield field blank, enter the actual yield and percent yield, and the calculator solves for theoretical yield.
Is a higher percent yield always better?
Generally yes for efficiency, but purity matters too. A high percent yield with impure product is often worse than a lower yield of pure product.
Does percent yield tell me about reaction rate?
No. Percent yield measures how much product you obtained relative to the maximum possible, not how fast the reaction occurred.
Is this calculator free to use?
Yes, completely free with no sign-up, and it runs entirely in your browser.