Chemistry Calculator Empirical Formula With Steps

Empirical Formula Calculator with Steps

Use this free empirical formula calculator to find the simplest whole-number ratio of elements in a compound using percent composition or mass data.

Calculate Empirical Formula

Enter each element symbol, its amount, and molar mass. If you are using percent composition, enter the percent values as if you have a 100 g sample.

Result:
—

How to Find an Empirical Formula

An empirical formula shows the simplest whole-number ratio of atoms in a compound. It does not always show the actual number of atoms in one molecule.

mass or percent → moles → divide by smallest mole value → whole-number ratio
  1. Convert each element amount to moles.
  2. Divide every mole value by the smallest mole value.
  3. Multiply if needed to make whole numbers.
  4. Write the empirical formula using the final ratio.

Worked Example

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen.

C: 40.0 ÷ 12.01 = 3.33 mol
H: 6.7 ÷ 1.008 = 6.65 mol
O: 53.3 ÷ 16.00 = 3.33 mol
Ratio: C₁H₂O₁

The empirical formula is CH₂O.

Practice Question

A compound contains 52.2% carbon, 13.0% hydrogen, and 34.8% oxygen. What is the empirical formula?