Worked example
For CaCO₃ → CaO + CO₂, choose CaO as the desired product. With coefficient 1 throughout, 100.086 g/mol CaCO₃ and 56.077 g/mol CaO give about 56.03% atom economy. The remaining 44.009 g per reaction unit corresponds to the other product.
Include every stoichiometric reactant
A coefficient multiplies the molar mass: 2 H₂ contributes 2 × 2.016 g per reaction unit. Add a row for each reactant consumed by the balanced equation. A catalyst or solvent that is not consumed in that equation is outside this particular metric.
Atom economy and percent yield answer different questions
Atom economy is a theoretical mass fraction derived from the equation. Percent yield compares actual isolated product with its theoretical yield. A reaction can have a high percent yield while sending much of its reactant mass into other products.
Check the equation before trusting the percentage
This tool does not balance reactions or verify chemical identity. The desired-product mass cannot exceed total reactant mass. That check catches some entry errors but does not prove an equation is balanced. The single desired-product model excludes solvent use, excess feed, energy and hazard; it is not an overall sustainability rating.
Explore the related calculation
For a different starting point, try the percent-yield calculator or return to the main calculator. Browse the complete tool directory for this site.
Reference and corrections
The definitions and assumptions above follow these sources; the examples and calculator arithmetic are original to this page.
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