Empirical Formula Calculator (C=42.8% O=57.1%)

Calculated Empirical Formula

Empirical Formula: CO (CARBON MONOXIDE)
Element Entered Percentage Actual Percentage
Carbon 42.8 42.88
Oxygen 57.1 57.12


This program determines both empirical and molecular formulas. To calculate the empirical formula, enter the composition (e.g. C=40%, H=6.67%, O=53.3%) of the compound. Enter an optional molar mass to find the molecular formula.

  • Percentages can be entered as decimals or percentages (i.e. 50% can be entered as .50 or 50%.)
  • To determine the molecular formula, enter the appropriate value for the molar mass.
  • Use uppercase for the first character in the element and lowercase for the second character. Examples: Fe, Au, Co, Br, C, O, N, F.

How To Determine Empirical/Molecular Formulas

Read our article on how to determine empirical and molecular formulas.

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