Percent Yield Calculator
Compare recovered product with its theoretical amount and express the recovery as a percentage.
01 Set up your calculation
- Enter the mass of product recovered.
- Enter its theoretical maximum based on the limiting reactant.
- Read the percentage and investigate any value above 100%.
02 The relationship
For the assumptions behind these results, read the explanation below. You can also explore Actual Yield and Theoretical Yield.
Follow the numbers
Recovering 18 g when 24 g is theoretically possible gives 100 × 18/24 = 75% yield.
03 Set a consistent comparison
A meaningful percentage compares the same chemical species in the numerator and denominator. If the product is hydrated, solvated, impure, or still in solution, account for that basis before comparing masses.
Theoretical yield comes from a balanced reaction and the amount of limiting reagent. It is not simply the mass of all starting materials added together.
04 Using yield to understand an experiment
A percentage below 100% quantifies the shortfall but does not diagnose it. Product can remain in solution, be lost in transfer, decompose, or fail to form. Conversion of a starting material and isolated yield of the desired product are different measurements.
A result above 100% is displayed because it is useful as a diagnostic. Recheck the dry mass, purity, hydrate state, molar masses, and limiting reagent rather than treating it as a more efficient-than-possible reaction.
Questions from the notebook
Why is theoretical yield required to be positive?
It is the denominator. A percentage relative to zero cannot be defined.
Does 75% yield mean 75% purity?
No. Yield measures recovered amount relative to a theoretical basis; purity measures composition.
Are different mass units allowed?
Yes. Unit controls convert the masses to a common base before division.
References & reading
- OpenStax, Rice University — Reaction Yields ↗
Defines actual, theoretical, and percentage yield and explains limiting-reactant calculations.
- NIST — Guide to SI conversion factors ↗
Supports physical unit conversions. Input values are converted to the formula’s base units before calculation.
Our explanations are written for ChemistryCalc. Read how we build and check our tools. These calculations are educational estimates where the underlying model requires assumptions.