Molar Mass Calculator | Molecular Weight Calculator

Molar mass (also called molecular weight or molecular mass) is the mass of one mole of a substance, expressed in grams per mole (g/mol). It's calculated by adding up the atomic weights of all atoms in a chemical formula.

For example, to find the molar mass of H₂O (water), add the atomic mass of hydrogen (1.008 g/mol) multiplied by 2, plus the atomic mass of oxygen (15.999 g/mol): (2 × 1.008) + 15.999 = 18.015 g/mol.

Using our molar mass calculator is simple:

1. Enter a chemical formula in the input field (e.g., H2O, NaCl, C6H12O6)
2. Watch as the calculator instantly calculates the molar mass as you type
3. View the total molar mass and detailed element breakdown

The calculator follows standard chemical notation. For example, use H2O for water, C6H12O6 for glucose, and NaCl for sodium chloride. For elements with two-letter symbols, capitalize only the first letter (e.g., Na for sodium, Cl for chlorine).

Knowing the molar mass of a compound is essential for various chemical calculations:

• Stoichiometry calculations - Convert between mass and moles in chemical reactions
• Solution preparation - Calculate the mass needed to prepare a solution of a specific molarity
• Empirical formula determination - Compare experimental mass percentages with theoretical values
• Gas law calculations - Convert between mass and volume for gases
• Colligative properties - Calculate freezing point depression, boiling point elevation, etc.

In laboratory and industrial settings, accurate molar mass calculations are crucial for proper experimental design and process optimization.

The terms "molar mass" and "molecular weight" are often used interchangeably in chemistry, but there is a subtle difference:

• Molar mass refers to the mass of one mole of a substance and is expressed in grams per mole (g/mol)
• Molecular weight technically refers to the mass of one molecule relative to 1/12 the mass of carbon-12, making it dimensionless (or expressed in atomic mass units, amu)

In practice, the numerical values are identical, just with different units. This calculator provides the result in g/mol (molar mass), which is the most commonly used unit in chemical calculations.

This calculator uses precise atomic weight values from the latest International Union of Pure and Applied Chemistry (IUPAC) data, providing accuracy to four decimal places. It accounts for all elements in the periodic table and handles complex formulas with multiple elements and parentheses.

For most educational and laboratory applications, this precision is more than sufficient. However, for isotopically-labeled compounds or specialized research applications where isotopic distribution matters, additional considerations may be necessary.