What is the Empirical Formula Calculator?
The empirical formula is the simplest whole-number ratio of atoms in a compound. This calculator converts elemental composition — mass percent or absolute masses in grams — into moles, finds the mole ratio, and outputs the empirical formula (e.g. CH₂O from glucose analysis). Add two or more elements, use standard atomic weights, and get a step-by-step breakdown with mole ratios. Runs instantly in your browser with no signup.
How to use the Empirical Formula Calculator
- Choose mass percent (%) or absolute mass (g) input.
- Enter each element symbol and its composition value.
- Add or remove rows for additional elements.
- Read the empirical formula and mole-ratio table.
- Copy the summary for homework or lab reports.
Common use cases
- Finding CH₂O from 40% C, 6.67% H, 53.33% O (glucose composition)
- Getting CH from 92.3% carbon and 7.7% hydrogen (benzene)
- Converting gravimetric analysis masses to an empirical formula
Frequently asked questions
- What is an empirical formula?
- The empirical formula shows the simplest whole-number ratio of atoms in a compound. Glucose (C₆H₁₂O₆) has empirical formula CH₂O.
- How do I use mass percent data?
- Assume a 100 g sample: each mass percent equals grams of that element. Enter the percentages and the calculator converts them to moles.
- What if my percentages do not add to 100%?
- Small rounding differences are normal. The calculator warns if the total is far from 100% but still computes from your values.
- How is this different from molecular formula?
- Empirical formula is the reduced ratio. Molecular formula is a whole-number multiple — find it by comparing empirical formula mass to experimental molar mass.
