Empirical Formula Calculator (from % Composition)
Empirical formula calculator: simplest whole-number formula from percent composition, and the molecular formula from the molar mass.
C 40 % · H 6.71 % · O 53.29 % → CH2O
How to use this calculator
- Type your input in the box.
- The result updates as you type.
- Use “Copy result” or “Copy link” to share it.
Convert each percentage to moles, divide by the smallest, then multiply until all are whole numbers.
With the molar mass, the molecular formula is the empirical formula times M ÷ M(empirical).
Frequently asked questions
C 40 %, H 6.71 %, O 53.29 % and M = 180 g/mol?
Empirical CH₂O, molecular C₆H₁₂O₆ (glucose).