Mole to Gram Calculator
Converting between moles and grams is one of the most common calculations in chemistry. The molar mass of a substance (in g/mol) serves as the conversion factor: mass equals moles times molar mass. This calculator works in both directions. Enter moles and molar mass to get grams, or enter grams and molar mass to get moles. The molar mass of any compound can be found by summing the atomic masses of all atoms in its formula using a standard periodic table.
Mole-gram conversion formula
mass (g) = moles (mol) * molar mass (g/mol) moles (mol) = mass (g) / molar mass (g/mol)
Molar mass (M) has units of g/mol and equals the sum of atomic masses of all atoms in the chemical formula, using the IUPAC periodic table values.
Common molar masses
- Water (H(2)O): 18.015 g/mol
- Sodium chloride (NaCl): 58.440 g/mol
- Carbon dioxide (CO(2)): 44.009 g/mol
- Glucose (C(6)H(12)O(6)): 180.156 g/mol
- Calcium carbonate (CaCO(3)): 100.087 g/mol
Frequently asked questions
What is a mole in chemistry?
A mole is the SI unit for amount of substance. One mole contains exactly 6.02214076 x 10^23 particles (atoms, molecules, ions, etc.), known as Avogadro's number. It is the link between atomic-scale quantities and laboratory-scale masses.
What is molar mass?
Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It equals the sum of the atomic masses of all atoms in the formula. For example, water (H2O) has a molar mass of 2(1.008) + 15.999 = 18.015 g/mol.
How do I convert moles to grams?
Multiply the number of moles by the molar mass of the substance. Mass (g) = moles (mol) x molar mass (g/mol). For example, 2.5 mol of NaCl (molar mass 58.44 g/mol) = 2.5 x 58.44 = 146.1 g.
How do I convert grams to moles?
Divide the mass in grams by the molar mass. Moles = mass (g) / molar mass (g/mol). For example, 100 g of NaCl = 100 / 58.44 = 1.71 mol.
Where do I find molar masses?
Molar masses are calculated from atomic masses on the periodic table. The NIST Chemistry WebBook and standard periodic tables list atomic masses to four or more decimal places. Common substances: H2O = 18.015, CO2 = 44.009, NaCl = 58.440 g/mol.
Official sources
- NIST: NIST Chemistry WebBook - Molecular formulas and properties.
- IUPAC: IUPAC Periodic Table of Elements.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.