Molecular Weight Calculator
Calculate the molecular weight of chemical compounds based on their chemical formula. Enter any chemical formula and get instant results with detailed element composition.
Enter a chemical formula to calculate its molecular weight (e.g. C6H12O6 for glucose)
Common Chemical Formulas
Periodic Table Elements
| Element | Symbol | Atomic Weight |
|---|
Calculation Results
Elemental Composition
| Element | Count | Atomic Weight | Total Weight | Percentage |
|---|
Formula Interpretation
About Molecular Weight Calculation
The molecular weight (or molecular mass) of a compound is the sum of the atomic weights of all the atoms in its chemical formula. It's typically expressed in grams per mole (g/mol) and is essential for various chemistry calculations, including stoichiometry and solution preparation.
How to Use This Calculator
To calculate the molecular weight of a compound:
- Enter the chemical formula in the input field (e.g., H2O for water or C6H12O6 for glucose)
- Select whether the calculation should be case-sensitive (default) or case-insensitive
- Choose your preferred output unit (g/mol, kg/mol, or mg/mol)
- Click "Calculate" to see the results
Understanding the Results
The calculator provides several pieces of information:
- Molecular Weight: The total mass of one mole of the compound
- Elemental Composition: Breakdown of each element in the compound
- Percentage Composition: The mass percentage of each element in the compound
- Formula Interpretation: How the calculator parsed your input formula
Formula Formatting Rules
The calculator follows standard chemical notation rules:
Element Symbols
Element symbols start with a capital letter followed by lowercase letters (e.g., Na for sodium, Cl for chlorine).
Subscripts
Numbers after element symbols indicate the count of that atom (e.g., H2O has 2 hydrogen atoms).
Parentheses
Parentheses group atoms with subscripts (e.g., (NH4)2SO4 has two NH4 groups).
Calculation Formula
The molecular weight is calculated using the formula:
Molecular Weight = Σ(Atomic Weight × Count) for all elements in the formula
Where:
- Atomic Weight is the standard atomic mass of the element (from the periodic table)
- Count is the number of atoms of that element in the formula