How to Calculate Empirical & Molecular Formulas
Determine simplest mole ratio step-by-step:
Enter Elemental %
Enter element mass or percentage (e.g. C:40, H:6.7, O:53.3).
Convert Mass to Moles
Divide each element mass by its atomic molar mass (g/mol).
Divide by Smallest
Divide all mole counts by the smallest mole value to get ratio.
Scale to Whole Numbers
Multiply to integer subscripts for Empirical Formula & Molecular Formula.
Key Features & Analytical Chemistry
Combustion Analysis Input
Accepts arbitrary elemental percentages or gram mass values.
Fractional Ratio Scaling
Automatically detects half (.5), third (.33, .66), and quarter (.25, .75) ratios.
Molecular Weight Multiplier
Computes n-factor multiplier when experimental molar mass is provided.
Stoichiometry Guide: Empirical vs Molecular Formulas
The Empirical Formula represents the lowest whole-number integer ratio of atoms present in a compound. In contrast, the Molecular Formula specifies the exact number of atoms of each element in a single molecule.
For example, hydrogen peroxide has an empirical formula of HO (1:1 ratio) and a molecular formula of H₂O₂ (molar mass 34.01 g/mol).
Frequently Asked Questions
?Can empirical formula be identical to molecular formula?
Yes. For many compounds like water (H₂O), methane (CH₄), and carbon dioxide (CO₂), the simplest whole-number ratio is equal to the actual molecular formula (multiplier n = 1).