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Free empirical formula calculator & molecular formula calculator. Calculate empirical formulas from percent composition or mass data with step-by-step solutions. Our calculator uses stoichiometry principles to determine the simplest whole-number ratio of atoms in compounds and convert to molecular formulas.
Last updated: February 2, 2026
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Empirical Formula:
CH2O
Molar Amounts:
C: 3.3306 mol, H: 6.6468 mol, O: 3.3312 mol
Simplest Ratio:
C: 1.00, H: 2.00, O: 1.00
Calculation Steps:
1. Convert to moles 2. Divide by smallest 3. Round to whole numbers
Interpretation:
Empirical formula CH2O represents the simplest ratio of elements
Key Concepts:
Input types
Mass or Percent
Works with mass in grams or percent composition data
Formula
(Empirical)ₙ
Multiply empirical formula by whole number n using molar mass
Assume
100g total
Percentages convert directly to grams when assuming 100g sample
Process
Moles ÷ smallest
Divide all mole values by smallest to get simplest ratio
Key formula
moles = mass / atomic mass
Convert between mass and moles using atomic masses
Analysis
Complete solution
Full step-by-step analysis of chemical formula calculations
For compound with 40.0% C, 6.7% H, 53.3% O:
Empirical Formula
CH₂O
Our empirical formula calculator uses stoichiometric principles to determine the simplest whole-number ratio of atoms in a compound. The calculation converts mass or percent composition to moles, then finds the simplest integer ratio by dividing by the smallest value and multiplying to eliminate decimals.
This systematic approach ensures accurate determination of the simplest formula representing the compound's composition. The empirical formula may equal the molecular formula if already in simplest form.
Shows conversion from mass to moles to simplest ratio
Empirical formula determination relies on the mole concept - the fundamental unit in chemistry that relates mass to number of particles. Since atoms combine in whole-number ratios, we must convert mass (which varies by element) to moles (which count atoms). The atomic mass serves as the conversion factor: 1 mole of an element has a mass in grams equal to its atomic mass.
Need help with other chemistry tools? Check out our mole calculator and percent yield calculator.
Get Custom Calculator for Your PlatformResult: Empirical Formula = CH₂O
This is the simplest whole-number ratio. Molecular formula could be CH₂O, C₂H₄O₂, C₃H₆O₃, etc.
11.2% H, 88.8% O
Empirical: H₂O (also molecular)
40% C, 6.7% H, 53.3% O
Empirical: CH₂O, Molecular: C₆H₁₂O₆
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