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Empirical Formula Calculator

Find the empirical (and molecular) formula of a compound from its percent composition, free online.
About this calculator

Convert each element's mass percent to moles by dividing by its atomic mass, then divide every value by the smallest to get the simplest whole-number ratio (multiplying by 2โ€“6 when a ratio ends in .5, .33 or .25). Enter the molar mass to scale up to the molecular formula.