Overview
What Is an Empirical Formula Calculator?
This tool calculates a compound's empirical formula (simplest whole-number ratio of elements) from two elements' percent composition and atomic weights.
Calculate empirical formula from percent composition.
Element A
Element B
This tool calculates a compound's empirical formula (simplest whole-number ratio of elements) from two elements' percent composition and atomic weights.
Useful for stoichiometry problems involving determining a compound's formula from composition data.
Input its percentage composition and atomic weight.
Input the same for the second element.
The empirical formula ratio updates automatically.
The simplest whole-number ratio of atoms in a compound, which may or may not match the actual molecular formula.
Convert percent composition to moles (divide by atomic weight), then find the simplest whole-number ratio between elements.
Molecular formula shows the actual number of atoms; empirical formula shows the simplest ratio - molecular formula is always a whole-number multiple of empirical formula.
This calculator handles two elements - the same principle extends to more elements using the same ratio-finding method.
No, calculations happen entirely in your browser.
In real problems, percentages should sum to 100% (or close to it, accounting for rounding) - verify your input data.
Yes, empirical formula determination from experimental composition data is a classic chemistry technique.
Standard atomic weights are available on the periodic table for each element.
Yes, completely free with no sign-up required.