Molar Mass Calculator (Molecular Weight)

The molar mass of a chemical compound is a fundamental concept in chemistry, representing the mass of one mole of that substance. Expressed in grams per mole (g/mol), it’s essentially the weight of 6.022 x 10²³ (Avogadro’s number) particles of the compound. Understanding molar mass is crucial for various chemical calculations, from determining reactant quantities in a reaction to preparing solutions of a specific concentration.

Our molar mass calculator simplifies this often tedious process, providing accurate results in an instant.

Enter the formula and press “calculate” to work out the molecular mass, the number of moles in 1 g and the percentage by mass of each element.

Chemical symbols are case specific and should be entered correctly to prevent ambiguity – for example, Fe will work correctly but FE and fe will not.

You can use up to 12 different elements and brackets () and [] in your formula.

How to Calculate Molar Mass (The Manual Way)

Calculating the molar mass of a chemical formula manually involves a few straightforward steps:

1. Identify Each Element: Break down the compound into its constituent elements. For example, in H₂SO₄, you have Hydrogen (H), Sulfur (S), and Oxygen (O).
2. Find Atomic Mass: Look up the atomic mass of each individual element on the periodic table. These values are typically found below the element symbol.
3. Count Atoms: Determine the number of atoms for each element in the chemical formula. Subscripts indicate the number of atoms. For H₂SO₄, there are 2 Hydrogen atoms, 1 Sulfur atom, and 4 Oxygen atoms. Parentheses indicate groups of atoms multiplied by the subscript outside (e.g., in (NH₄)₂CO₃, there are 2 Nitrogen and 8 Hydrogen atoms).
4. Multiply & Sum: Multiply the atomic mass of each element by its number of atoms in the formula. Then, sum up these products to get the total molar mass of the compound.

While the manual calculation is good for understanding the principle, our online molar mass calculator handles all these steps automatically, saving you time and preventing errors.

Why Molar Mass is important in Chemistry

Molar mass plays a vital role across many areas of chemistry. It’s indispensable for:

• Stoichiometry: Accurately predicting the quantities of reactants and products in chemical reactions. Knowing the molar mass allows chemists to convert between mass and moles, which is essential for quantitative analysis.
• Solution Preparation: Calculating the precise amount of a substance needed to achieve a desired concentration in a solution.
• Empirical and Molecular Formula Determination: While our current tool focuses on molecular mass, molar mass is also a key component in deriving molecular formulas from empirical formulas.
• Gravimetric Analysis: Determining the amount of a substance present in a sample through weighing.

Whether you’re a student, researcher, or just have a general interest in chemistry calculations, a reliable molar mass calculator is an invaluable tool.

Using Our Online Molar Mass Calculator for Instant Results

Forget complex manual calculations! Our user-friendly molar mass calculator provides quick and precise results for any chemical formula. Simply enter your compound (e.g., NaCl, C₆H₁₂O₆, Al₂(SO₄)₃.18H₂O) into the input field, click “Calculate,” and instantly get:

• The total molar mass of the compound in g/mol.
• The percentage by mass of each individual element.
• The number of atoms and mass contributed by each element.

It’s the perfect tool for homework, lab work, or quick reference, designed to make your chemistry calculations easier and more accurate.