Empirical & Molecular Formula Calculator

List the elements one per line, each as a symbol and a number: C 40.0 means 40.0 of carbon in the units chosen below.

The tool turns these into a mole ratio and reduces it to the simplest whole numbers.

What the numbers you pasted represent.

• Mass percent: each element as a % of the total mass (should add to ~100).
• Grams: measured masses of each element.
• Moles: amounts already in moles.

Optional. The true molar mass of the whole compound. Leave blank for just the empirical formula.

If given, the tool scales the empirical formula up to the molecular formula — e.g. molar mass 180 turns CH₂O into C₆H₁₂O₆.