Molar Mass from Chemical Formula Calculator

Need a compound’s molar mass fast? Enter its chemical formula — including parentheses and hydrates like CuSO₄·5H₂O — and get an instant, element-by-element breakdown and total in g/mol.

Background

This calculator computes the molar mass of a compound directly from its chemical formula. It parses element symbols and subscripts (including parentheses and hydrates like CuSO₄·5H₂O), multiplies each element’s atomic weight by its count, and sums the total. Use this to check homework, prep labs, or build intuition for stoichiometry.

How to use the molar mass calculator

1) Type a valid chemical formula (case sensitive for element symbols).
2) Parentheses and nested groups are supported (e.g., Al₂(SO₄)₃).
3) Hydrates with a dot are supported (· or .), e.g., CuSO₄·5H₂O.
4) Click Calculate Molar Mass to see the breakdown and total.

Key Points

Atomic weights are IUPAC-typical values (to 3–4 sig figs).
For coursework, use the same atomic weights your class/teacher provides.
This tool computes the sum: Σ (count_element × atomic weight).

Formula & Equation Used

Total molar mass (M) is:

M = \sum_{}^{} n (element) \times AW (element)

n(element): number of atoms of that element in the formula unit
AW(element): atomic weight (g/mol)

Example Problems & Step-by-Step Solutions

Example 1:

Find the molar mass of glucose, C₆H₁₂O₆.

C: 12.011 × 6 = 72.066 g/mol
H: 1.008 × 12 = 12.096 g/mol
O: 15.999 × 6 = 95.994 g/mol
Total = 72.066 + 12.096 + 95.994 = 180.156 g/mol ≈ 180.16 g/mol

Example 2:

Find the molar mass of calcium hydroxide, Ca(OH)₂.

Ca: 40.078 × 1 = 40.078 g/mol
O: 15.999 × 2 = 31.998 g/mol
H: 1.008 × 2 = 2.016 g/mol
Total = 40.078 + 31.998 + 2.016 = 74.092 g/mol ≈ 74.09 g/mol

Frequently Asked Questions

Q: Do hydrates work (e.g., CuSO₄·5H₂O)?

Yes—use a dot (·) or period (.) between parts. The calculator multiplies each hydrate part correctly.

Q: Are parentheses supported?

Yes. Parentheses and nesting are supported: Al₂(SO₄)₃, Ca(OH)₂, etc.

Q: Which atomic weights are used?

Standard IUPAC-style atomic weights (typical table values). For strict grading, match your course’s table.