About the Empirical Formula Calculator
Find the empirical formula from percent composition or masses, and the molecular formula from molar mass.
Also known as: simplest formula, empirical to molecular formula, formula from percentages, combustion analysis.
How to use this calculator
- Enter element 1 symbol, percent or mass, element 2 symbol, percent or mass and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
Divide each element’s moles by the smallest, then scale to whole numbers
Worked example
Using the values pre-filled in the calculator above:
- Element 1 symbol: C
- Percent or mass = 40
- Element 2 symbol: H
- Percent or mass = 6.7
- Element 3 symbol: O
- Percent or mass = 53.3
- Element 4 symbol:
- Percent or mass = 0
the calculator returns:
- Empirical formula: CH2O
- Empirical formula mass: 30.026 g/mol
- Molecular formula: C6H12O6
- Multiplier: 6