🎓 Chemistry • Stoichiometry
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Empirical Formula Calculator
Converts percent mass or gram compositions into the simplest integer empirical formula.
Real-World Substance Presets1-click populate
Constituent Elements (% Mass or Grams)
Input percentage or grams of each element (e.g. C, H, O, N, S, Fe).
#1
Carbon (12.011)
% or g
#2
Hydrogen (1.008)
% or g
#3
Oxygen (15.999)
% or g
Total Mass Sum: 100%✓ Balances near 100%
Simplest Empirical Formula
CH2O
Empirical Formula Unit Weight: 30.026 g/mol
| Element | Mass (%) | Molar Mass | Moles (m/M) | Mole Ratio | Subscript |
|---|---|---|---|---|---|
| C (Carbon) | 40% | 12.011 g/mol | 3.3303 mol | 1.000 | 1 |
| H (Hydrogen) | 6.71% | 1.008 g/mol | 6.6567 mol | 1.999 | 2 |
| O (Oxygen) | 53.29% | 15.999 g/mol | 3.3308 mol | 1.000 | 1 |
What is an Empirical Formula?
An empirical formula represents the simplest whole-number ratio of atoms of each element present in a compound.
Formula & Step-by-Step Calculation
Ratio = (Mass / Atomic Weight) / Min(Moles)
Convert mass to moles, divide by smallest mole value, multiply by common integer factors.
Worked Step-by-Step Examples
Example 1
Compound with 40.0% C, 6.7% H, and 53.3% O
Solution: Empirical Formula: CH2O
• C: 3.33 mol, H: 6.65 mol, O: 3.33 mol ⟹ Ratio 1 : 2 : 1
Common Real-World & Academic Use Cases
- ✓ Determining unknown compound formulas from combustion analysis
- ✓ Mineralogical identification
- ✓ Organic synthesis verification
How to Use the Empirical Formula Calculator
1
Enter Element Symbols
Input chemical element symbols.
2
Input % Mass
Enter percentages or grams.
3
Read Empirical Formula
Inspect derived integer formula.
Frequently Asked Questions
Q: What is the difference between empirical and molecular formulas?
The empirical formula is the simplest integer ratio; the molecular formula gives the actual number of atoms in a molecule.