Molecular Formula Calculator

Calculate the whole-number multiple between empirical-formula mass and molecular molar mass, with a tolerance warning when the ratio is not close to an integer.

Empirical formula

Measured molar mass (g/mol)

—The measured molar mass should be near an integer multiple of the empirical-formula mass.

How to use this Molecular Formula Calculator

Find a molecular formula from an empirical formula and measured molar mass. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.