Atom Economy Calculator
A free chemistry calculator that uses a balanced chemical equation to show what percentage of the reactant mass becomes the desired product.
What the calculator does
- Accepts a balanced chemical equation.
- Checks that the equation is balanced.
- Calculates the relative mass of every reactant.
- Uses the equation coefficients in the mass calculation.
- Allows the desired product to be selected.
- Displays every stage of the atom-economy calculation.
The calculation
mass of desired product
÷
total mass of reactants
× 100
A higher atom economy means that more of the reactant atoms appear in the desired product.
Open the calculator
Enter a balanced equation or select a worked example.
Launch Atom Economy CalculatorThe calculator opens in a new browser tab.
How to Use the Atom Economy Calculator
1. Enter a balanced equation
Type the complete chemical equation, placing the equation coefficients before the formulae.
For example:
When typing into the calculator, use spaces around the plus sign and enter the arrow as ->.
Formulae are case-sensitive. For example, calcium chloride must be entered as CaCl2, not Cacl2.
2. Check that the equation is balanced
The calculator compares the number of atoms of every element on the two sides of the equation.
Atom economy must be calculated from a balanced equation because the equation coefficients determine the relative masses involved.
3. Select the desired product
If the reaction produces more than one product, select the product that is required.
The other products are treated as waste products for the purpose of the atom-economy calculation.
4. Follow the relative-mass calculation
The calculator determines the relative formula mass, Mr, of each reactant and multiplies it by its equation coefficient.
These values are added to obtain the total relative mass of the reactants.
5. Calculate the useful mass
The relative formula mass of the desired product is also multiplied by its equation coefficient.
The calculator then applies:
coefficient × Mr of desired product
÷
total coefficient × Mr of reactants
× 100
6. Interpret the answer
The result is the percentage of the total reactant mass that becomes the desired product.
A reaction with an atom economy of 100% produces only the desired product. A lower value means that some of the reactant atoms form other products.
Atom economy is not percentage yield
Atom economy is a theoretical measure determined from the balanced equation.
Percentage yield compares the amount of product actually obtained with the theoretical amount that could have been produced.