⚗️ Molar Mass Calculator

Enter a chemical formula to calculate its molar mass in g/mol.

Chemical Formula

Supports parentheses: Ca(OH)2, Al2(SO4)3

— g/mol

Molar Mass

How to Use This Calculator

This tool calculates the molar mass of any chemical compound by summing the atomic masses of every atom in the formula. Type the formula using standard notation, and the calculator returns the result in grams per mole (g/mol) along with a per-element breakdown.

Type your chemical formula in the input box, for example H2O, NaCl, or C6H12O6. Capitalise element symbols correctly: Ca, not ca or CA.

For polyatomic groups, use parentheses as you would on paper: Ca(OH)2, Al2(SO4)3, Fe2(CO3)3.

Click Calculate or just pause typing. The result updates automatically after 400 ms.

Read the molar mass in g/mol at the top, then scroll the breakdown table to see each element's contribution.

Molar Mass Formula

M = Σ (atomic_mass_of_element × count_in_formula)

Each element's atomic mass comes from the periodic table in atomic mass units (amu), which are numerically equal to g/mol. For water, that is 2 × 1.008 (hydrogen) + 1 × 15.999 (oxygen) = 18.015 g/mol. For glucose (C₆H₁₂O₆): 6 × 12.011 + 12 × 1.008 + 6 × 15.999 = 180.156 g/mol. You multiply each element's standard atomic mass by how many times it appears in the formula, then add all the products together.

Worked Examples

Water (H₂O): 2(1.008) + 15.99918.015 g/mol

Table salt (NaCl): 22.990 + 35.45358.443 g/mol

Glucose (C₆H₁₂O₆): 6C + 12H + 6O180.156 g/mol

Sulfuric acid (H₂SO₄): 2H + S + 4O98.079 g/mol

Where This Calculation Comes Up

Any time you weigh a chemical in the lab, you need molar mass to convert grams to moles. If a procedure asks you to prepare 0.25 mol of NaCl, you multiply 0.25 by 58.443 g/mol to get 14.6 g. Without that conversion, you cannot follow a stoichiometric recipe. This shows up in titrations, solution preparation, gravimetric analysis, and every reaction where you need a specific number of moles rather than a specific number of grams.

In general chemistry coursework, molar mass questions appear on nearly every exam. You will use it when calculating empirical formulas from percent composition, when working limiting reagent problems, and when finding theoretical yield. Professionals in pharmaceutical manufacturing, food science, and materials research also rely on it daily. Knowing the molar mass of aspirin (C₉H₈O₄, 180.157 g/mol) tells a pharmacist how many molecules are in a 500 mg tablet.

Frequently Asked Questions

What is molar mass?

Molar mass is the mass of one mole (6.022×10²³ particles) of a substance, expressed in grams per mole (g/mol). It equals the sum of atomic masses of all atoms in the formula.

How do I enter a chemical formula?

Type the element symbol with capital first letter, followed by the count in digits. Examples: H2O (water), NaCl (table salt), C6H12O6 (glucose), Ca(OH)2 (calcium hydroxide).

What is the difference between molar mass and molecular weight?

They are numerically identical. Molecular weight is a dimensionless ratio, while molar mass carries the unit g/mol.

Can I use parentheses in formulas?

Yes! The calculator handles nested parentheses like Ca(OH)2, Al2(SO4)3, Fe2(CO3)3, etc.

Why does my result show "unknown element"?

Check that element symbols are correctly capitalised (e.g., "Ca" not "ca") and that the symbol exists on the periodic table.