Determine the molecular formula from the empirical formula and measured molar mass.
The molecular formula is always a whole-number multiple of the empirical formula. Glucose has an empirical mass of 30.03 and a molar mass of 180.16, giving a multiplier of six and the formula C₆H₁₂O₆. A multiplier that is not close to a whole number signals an error in either the composition data or the molar mass determination.
Molecular Formula
Multiplier = molar mass ÷ empirical formula mass, rounded to the nearest whole number
Multiplier = molar mass ÷ empirical formula mass, rounded to the nearest whole number The molecular formula is always a whole-number multiple of the empirical formula. Glucose has an empirical mass of 30.03 and a molar mass of 180.16, giving a multiplier of six and the formula C₆H₁₂O₆.
A multiplier that is not close to a whole number signals an error in either the composition data or the molar mass determination.
This calculator takes 2 inputs: Empirical formula mass, Measured molar mass. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.