Atom Economy Calculator

This calculator finds the atom economy of a chemical reaction, a key measure of efficiency and sustainability in green chemistry. Atom economy asks a simple but important question: of all the atoms in the starting materials, what fraction end up in the product you actually want? It is calculated as the molar mass of the desired product divided by the total molar mass of all the reactants, expressed as a percentage. A reaction with high atom economy converts most of its reactant mass into useful product, wasting little, while one with low atom economy produces a lot of unwanted by-products that become waste. This matters enormously for sustainability and cost: even if a reaction gives a high yield, poor atom economy means much of the raw material is destined for the waste stream, with all the environmental and financial burden that brings. Atom economy is therefore one of the central principles of green chemistry, sitting alongside percentage yield as a measure of how good a reaction really is. The two are different: yield measures how much of the possible product you obtained, while atom economy measures how much of the reactants could ever become product even in principle. This tool computes it. You enter the molar mass of the desired product and the combined molar mass of all the reactants, and the calculator returns the percentage atom economy and the percentage that becomes waste. The results update as you type. Use it for chemistry study, for comparing synthetic routes, or for evaluating how green a process is. Addition reactions, where all the reactant atoms end up in a single product, have an ideal atom economy of 100 percent, while substitution and elimination reactions are inherently lower.

Atom economy = (molar mass of desired product / total molar mass of reactants) x 100. Addition reactions can reach 100%. Differs from percentage yield.