Molar Mass Calculator
From Chemical Formula
Enter a chemical formula like H2O, NaCl, Ca(OH)2
Mass to Moles
Moles to Mass
Formula
Molar Mass = Σ(atomic mass × number of atoms) | moles = mass / molar mass
Frequently Asked Questions
What is molar mass?
Molar mass is the mass of one mole (6.022 x 10^23 particles) of a substance, expressed in grams per mole (g/mol). It equals the sum of atomic masses of all atoms in the molecular formula. For example, H2O has a molar mass of 2(1.008) + 15.999 = 18.015 g/mol.
How do I calculate molar mass from a formula?
Add up the atomic masses of each element multiplied by its subscript. For Ca(OH)2: Ca = 40.078 + 2(O = 15.999 + H = 1.008) = 40.078 + 33.014 + 2.016 = 74.093 g/mol.
What is the difference between molar mass and molecular weight?
They are numerically the same but have different units. Molar mass is in g/mol while molecular weight (relative molecular mass) is dimensionless, expressed in atomic mass units (amu or Da).
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