Molar Mass Calculator
Molar mass of common compounds and mole conversion.
Enter your values
ⓘ Live results
Results
- Moles
- 0.9989 mol
- Number of molecules
- 6.015e+23
- Molar mass used
- 18.02 g/mol
Quick answer
Moles = mass (g) / molar mass (g/mol).
n = m / M
How to use the Molar Mass Calculator
- 1Enter the mass of your sample in grams.
- 2Enter the compound's molar mass (sum of atomic masses, or look it up on the periodic table).
- 3Read the number of moles and molecules present.
Worked example
Using the values the calculator loads with:
Inputs
- Sample mass18 g
- Molar mass18.02 g/mol (water default)
Results
- Moles0.9989 mol
- Number of molecules6.015e+23
- Molar mass used18.02 g/mol
Frequently asked questions
How do I find molar mass myself?
Add up the atomic masses of every atom in the formula, e.g. H2O = 2(1.008) + 16.00 = 18.02 g/mol.
What is Avogadro's number used for here?
It converts moles to the actual number of molecules or atoms present, 6.022e23 per mole.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.