Atom Economy Calculator
Enter the molar mass of the desired product and the total molar mass of reactants to compute atom economy: AE% = desired product ÷ total reactants × 100%.
Input Data
Results
At a glance:Enter the molar mass of the desired product and the total molar mass of reactants to compute atom economy: AE% = desired product ÷ total reactants × 100%.
Formula
AE% = (desired product molar mass ÷ total reactant molar mass) × 100%.
How to Use
- Enter the molar mass of the desired product (times its coefficient).
- Enter the total molar mass of all reactants (each times its coefficient).
- The calculator returns the atom economy AE%.
FAQ
How is atom economy different from yield?
Yield measures the actual output as a percentage of the theoretical maximum, reflecting whether the reaction went to completion and whether there was loss. Atom economy measures, even at 100% completion, how wasteful the equation is at the atomic level, reflecting the inherent efficiency of the reaction design. A reaction can have high yield but low atom economy; an ideal green reaction is high in both.
Which reactions have the highest atom economy?
Addition and rearrangement reactions are highest, reaching 100%, because every reactant atom is incorporated into the product with no by-products. Substitution is moderate, while elimination and condensation are lower because they release small by-product molecules such as water or hydrogen halides.
How do I choose the numerator and denominator?
Both must follow the balanced equation's stoichiometric coefficients. The numerator is the target product's coefficient × molar mass; the denominator is the sum of each reactant's coefficient × molar mass. If there are multiple desired products, include all of them in the numerator.
Can atom economy exceed 100%?
A normal reaction cannot. By mass conservation, total product mass equals total reactant mass, and the desired product is only part of it, so AE ≤ 100%. This calculator clamps anomalous inputs to 100%. AE = 100% means no by-product at all.
Why does green chemistry value atom economy?
High atom economy means little raw-material waste and few by-products (waste), lowering production cost and environmental burden. It is a quantitative indicator for the green-chemistry principles of 'waste prevention' and 'atom economy', and is especially important in pharmaceuticals and fine chemicals.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.