Percent Yield

Also known as actual over theoretical

\%\,\text{yield} = \frac{m_{\text{actual}}}{m_{\text{theoretical}}} \times 100\%

sig figs

Worked example: 4.10 g isolated of 5.00 g theoretical → 82% yield. Press Try an example to run it live, then adjust anything.

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Stoichiometry basics5 formulas

Yield on the batch record →

UniversityProcess & Water Chemistry

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Percent Yield explained

A balanced equation promises a certain mass of product; the flask rarely delivers all of it. Side reactions consume reactant, some product stays dissolved in the mother liquor, and a little is always lost on filter paper and glassware. Percent yield is the honest scorecard: the mass you actually isolated divided by the stoichiometric maximum, times 100. In a classic teaching lab, synthesizing aspirin from salicylic acid might predict 5.00 g of product; if 4.21 g of dry crystals come off the funnel, the yield is 84.2%.

The number matters far beyond the classroom. Process chemists judge manufacturing routes largely by yield, because in a multi-step synthesis losses multiply: five steps at 80% each deliver only 33% overall. A reported yield above 100% is a red flag, not a triumph: it usually means the product is still wet or carries impurities.

Percent Yield formula

\%\,\text{yield} = \frac{m_{\text{actual}}}{m_{\text{theoretical}}} \times 100\%

Where

$\%\,\text{yield}$ = Percent yield (%)
$m_{\text{actual}}$ = Actual yield (mass obtained) (kg)
$m_{\text{theoretical}}$ = Theoretical yield (mass predicted) (kg)

In this toolkit

Stoichiometry basics

5 formulasThe conversions every mass-to-mass calculation runs through — moles from grams, particles from moles, gas volume, composition and yield.

Revised 16 October 2026

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formula.expert. (2026, October 16). Percent Yield Formula & Calculator. https://formula.expert/solvers/percent-yield

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