Molar Mass Calculator
Calculate the molar mass (molecular weight) of any chemical compound. Enter a formula like H₂O, NaCl, or C₆H₁₂O₆ and get the molar mass with a detailed element-by-element breakdown. Supports parentheses, hydration, and compound formulas.
Common Compounds & Their Molar Masses
Here are the molar masses of some frequently used chemical compounds. Click the formula to copy it into the calculator above.
| Compound Name | Formula | Molar Mass (g/mol) |
|---|---|---|
| Water | H₂O | 18.015 |
| Carbon Dioxide | CO₂ | 44.010 |
| Sodium Chloride (Table Salt) | NaCl | 58.443 |
| Glucose | C₆H₁₂O₆ | 180.156 |
| Hydrochloric Acid | HCl | 36.461 |
| Sulfuric Acid | H₂SO₄ | 98.079 |
| Sodium Hydroxide (Lye) | NaOH | 39.997 |
| Calcium Carbonate | CaCO₃ | 100.087 |
| Ammonia | NH₃ | 17.031 |
| Methane | CH₄ | 16.043 |
| Ethanol | C₂H₅OH | 46.068 |
| Copper(II) Sulfate Pentahydrate | CuSO₄·5H₂O | 249.685 |
What Is Molar Mass?
Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is numerically equal to the molecular weight of a compound. One mole contains exactly 6.02214076 × 10²³ particles (Avogadro's number).
The molar mass of a compound is calculated by summing the atomic masses of all atoms in its chemical formula. For example, water (H₂O) has two hydrogen atoms (each ~1.008 g/mol) and one oxygen atom (~16.00 g/mol), giving a molar mass of 18.015 g/mol.
How to Calculate Molar Mass
- Identify the formula: Write the chemical formula (e.g., H₂O, NaCl, C₆H₁₂O₆).
- Count atoms: Determine the number of atoms of each element present.
- Look up atomic masses: Use the standard atomic weights from the periodic table.
- Multiply and sum: Multiply each element's atomic mass by its count, then add all contributions.
Example: Molar mass of glucose (C₆H₁₂O₆)
Carbon: 6 × 12.011 = 72.066 g/mol
Hydrogen: 12 × 1.008 = 12.096 g/mol
Oxygen: 6 × 16.000 = 96.000 g/mol
Total: 180.162 g/mol
Why Use This Molar Mass Calculator?
- Instant Results: Get molar mass calculations in seconds.
- Supports Complex Formulas: Handles parentheses, subscripts, and hydrates (e.g., CuSO₄·5H₂O).
- Element Breakdown: See the contribution of each element to the total mass.
- Visual Chart: Understand the composition at a glance.
- Common Names: Option to display common names for compounds.
- Free & Private: No registration, no data storage.
Molar Mass vs. Molecular Weight
The terms molar mass and molecular weight are often used interchangeably. Molecular weight (or molecular mass) is the mass of a single molecule expressed in atomic mass units (amu), while molar mass is the mass of one mole of molecules expressed in grams per mole (g/mol). Numerically, they are the same.
Applications of Molar Mass
- Stoichiometry: Converting between grams and moles in chemical reactions.
- Solution Preparation: Calculating how much solute is needed for a desired concentration.
- Analytical Chemistry: Identifying unknown compounds by mass spectrometry.
- Pharmaceuticals: Determining dosages and drug formulations.
- Environmental Science: Measuring pollutant concentrations.
❓ Molar Mass Calculator FAQ
What is molar mass?
Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in the chemical formula.
How do I calculate molar mass?
Multiply the atomic mass of each element by the number of atoms of that element in the formula, then sum all contributions. For example, H₂O: (2 × 1.008) + (1 × 16.000) = 18.016 g/mol.
What is the difference between molar mass and molecular weight?
Molar mass is expressed in g/mol and refers to one mole of molecules. Molecular weight (or molecular mass) is expressed in amu and refers to a single molecule. Numerically, they are identical.
What formulas are supported by this calculator?
The calculator supports chemical formulas with element symbols, subscripts, parentheses (e.g., Ca(OH)₂), and hydrates (e.g., CuSO₄·5H₂O). It handles both uppercase and lowercase letters correctly.
What is Avogadro's number?
Avogadro's number is 6.02214076 × 10²³. It represents the number of particles (atoms, molecules, or formula units) in one mole of a substance.
What is the molar mass of water?
The molar mass of water (H₂O) is 18.015 g/mol (2 × 1.008 + 16.000).
What is the molar mass of sodium chloride (NaCl)?
The molar mass of sodium chloride is 58.443 g/mol (22.990 + 35.453).
What is the molar mass of glucose (C₆H₁₂O₆)?
The molar mass of glucose is approximately 180.156 g/mol.
How does this calculator handle parentheses?
The calculator parses parentheses correctly. For example, Ca(OH)₂ is interpreted as Ca + 2O + 2H, giving the correct molar mass.
What is a hydrate formula?
A hydrate is a compound that contains water molecules as part of its structure. For example, CuSO₄·5H₂O (copper(II) sulfate pentahydrate) contains five water molecules per formula unit. This calculator supports hydrate notation using the asterisk (*) or dot (·).
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required. All calculations are performed in your browser.
What atomic mass values are used?
The calculator uses the IUPAC standard atomic weights. These are the most up-to-date values recommended by the International Union of Pure and Applied Chemistry.