Atom Economy Calculator
Calculate atom economy for any chemical reaction to measure efficiency and waste. High atom economy is a key principle of green chemistry. Enter your balanced equation and target product to see atom economy percentage and E-factor.
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What is atom economy?
Atom economy measures how efficiently atoms in reactants are incorporated into the desired product. Higher atom economy means less waste. It's critical for green chemistry: % atom economy = (MM of target product) / (sum MM of all reactants) × 100. Reactions with atom economy near 100% use all atoms efficiently.
How do I calculate atom economy?
Atom economy = (mass of target product atoms) / (mass of all reactant atoms) × 100. For balanced equation: 2Na + Cl₂ → 2NaCl, target is NaCl. Product atoms: 2×(22.99+35.45)=116.88. Reactant atoms: 2×22.99 + 2×35.45 = 116.88. Atom economy = 116.88/116.88 × 100 = 100%. All atoms incorporated!
What's a good atom economy?
Target: 100% — no waste. Addition reactions: often 100% (all atoms used). Substitution: typically 50-90%. Elimination: lower due to byproducts. Industrial processes aim for >80% atom economy to minimize waste and disposal costs. Low atom economy = lots of byproducts = environmental concerns.
What is E-factor?
E-factor (Environment factor) = kg waste per kg product = (100/atom_economy) - 1. For 50% economy: E = (100/50) - 1 = 1 kg waste/kg product. Higher E means more waste. Industry targets: <1 for bulk chemicals, <5 for fine chemicals, <100 for pharmaceuticals.
Why does atom economy matter in synthesis?
Atom economy directly impacts waste, cost, and environmental footprint. High atom economy = less solvent, less energy for separation, cheaper disposal, smaller waste streams, greener process. The U.S. EPA and green chemistry initiatives prioritize atom economy as a key metric for process evaluation and improvement.
How can I improve atom economy?
Changes to reaction design: use addition not substitution, select different transformations that incorporate more atoms, recover and recycle byproducts, use催化而非 stoichiometric reagents, design convergent syntheses to save steps. Each improvement reduces both waste and cost.