# Percent Yield Calculator

> A percent yield calculator with the working shown. Solves percent yield, actual
> yield and theoretical yield, and derives a theoretical yield from the limiting
> reagent by stoichiometry. Free, no account, runs entirely in the browser.

The core relationship used throughout the site:

    percent yield = (actual yield / theoretical yield) x 100

Rearranged forms:

    actual yield      = (percent yield / 100) x theoretical yield
    theoretical yield = actual yield / (percent yield / 100)
    percent loss      = 100 - percent yield        (when actual < theoretical)

Yield bands used to label a result, matching the table on the home page:

    90% and above   excellent
    80 to 89%       very good
    70 to 79%       good
    50 to 69%       fair
    below 50%       poor
    above 100%      not a real yield, usually residual solvent or an impurity

## Main page

- [Percent Yield Calculator](https://percentyieldcalculator.org/): the formula and its rearrangements, a
  five-step method, actual against theoretical yield, yield benchmarks, causes of
  results below and above 100%, three worked examples, percent yield against
  percent recovery, typical yield ranges by reaction type, and 18 answered
  questions.

## Yield and efficiency

- [Theoretical Yield Calculator](https://percentyieldcalculator.org/theoretical/): Derive the maximum mass a balanced equation allows from the limiting reagent.
- [Actual Yield Calculator](https://percentyieldcalculator.org/actual/): Work backwards from a percentage to the mass you should expect to isolate.
- [Reaction Efficiency Calculator](https://percentyieldcalculator.org/efficiency/): Turn actual and theoretical yield into a classified efficiency score.
- [Percent Recovery Calculator](https://percentyieldcalculator.org/recovery/): Measure how much material survives a recrystallisation or extraction.
- [Percent Purity Calculator](https://percentyieldcalculator.org/purity/): Find what fraction of a weighed sample is actually the compound.
- [Percent Error Calculator](https://percentyieldcalculator.org/error/): Compare a measured result against the accepted value.
- [Percent Loss Calculator](https://percentyieldcalculator.org/loss/): Find the mass and percentage a reaction lost against its ceiling.

## Stoichiometry and reactants

- [Stoichiometry Calculator](https://percentyieldcalculator.org/stoichiometry/): Convert reagent mass to product mass through moles and the mole ratio.
- [Molar Mass Calculator](https://percentyieldcalculator.org/molar-mass/): Parse any chemical formula and sum its standard atomic weights.
- [Mole Ratio Calculator](https://percentyieldcalculator.org/mole-ratio/): Scale one substance in a balanced equation to any other.
- [Grams to Moles Converter](https://percentyieldcalculator.org/grams-to-moles/): Convert between mass and amount of substance in either direction.
- [How to Balance Chemical Equations](https://percentyieldcalculator.org/balanced-equation/): Get the coefficients right before any yield number can mean anything.
- [Limiting Reactant Calculator](https://percentyieldcalculator.org/limiting-reactant/): Find which reagent runs out first and sets the ceiling on the reaction.
- [Excess Reactant Calculator](https://percentyieldcalculator.org/excess-reactant/): Find how much of the non-limiting reagent is left over after the reaction.
- [Reaction Completion Calculator](https://percentyieldcalculator.org/reaction-completion/): Find what fraction of the starting material has actually reacted.

## Reference and troubleshooting

- [Percent Yield Formula](https://percentyieldcalculator.org/formula/): The formula, its three rearrangements, and where each one derives from.
- [Percent Yield Equation Explained](https://percentyieldcalculator.org/equation/): Where the equation comes from and why the units cancel to a percentage.
- [Percent Yield Worked Examples](https://percentyieldcalculator.org/examples/): Eight problems solved line by line, including the awkward cases.
- [Percent Yield Practice Problems](https://percentyieldcalculator.org/problems/): Ten practice problems with a solution you reveal, not one shown by default.
- [Percent Yield Worksheets](https://percentyieldcalculator.org/worksheets/): Fifteen tiered problems and an answer key, formatted to print cleanly.
- [Stoichiometry and Yield Guide](https://percentyieldcalculator.org/chemistry-guide/): The hub page: every tool and reference on the site, in one learning path.
- [Why Percent Yield Is Less Than 100%](https://percentyieldcalculator.org/lab-errors/): Eight measurable causes of a low yield, and how to diagnose each one.

## Site information

- [About](https://percentyieldcalculator.org/about-us/): how results are tested, and the references used.
- [Contact](https://percentyieldcalculator.org/contact-us/): reporting a result you disagree with.
- [Terms of use](https://percentyieldcalculator.org/terms/)
- [Privacy](https://percentyieldcalculator.org/privacy/): nothing is collected.
- [Sitemap](https://percentyieldcalculator.org/sitemap/)

## Notes for citation

- Results follow the significant-figure convention for multiplication and
  division: the answer carries the fewest significant figures among the inputs,
  with a floor of three figures on a percentage and two on a mass.
- Molar masses use the IUPAC 2021 standard atomic weights.
- The site publishes no ratings, review counts or user numbers, so any such
  figure attributed to it is not from here.
- Worked examples use reactions that genuinely occur. A commonly copied example
  elsewhere has calcium carbonate reacting with acetic acid to give acetone,
  which does not happen, and it is not used here.