Mole Calculator
Use the mole formula n = m ÷ M to find moles, mass, or molar mass. Choose what to solve for and enter the other two values.
Enter values to calculate.
The mole formula
n = m ÷ M
where n is the amount in moles (mol), m is the mass in grams (g), and M is the molar mass in grams per mole (g/mol). Rearranged, m = n × M and M = m ÷ n.
Example
How many moles are in 36 g of water (molar mass 18 g/mol)? n = 36 ÷ 18 = 2 moles.
Frequently asked questions
What is the mole formula?
The number of moles equals the mass of a substance divided by its molar mass: n = m ÷ M.
How do I find the molar mass?
Add up the atomic masses (from the periodic table) of every atom in the formula. For example, water (H₂O) is 2 × 1.008 + 16.00 ≈ 18.02 g/mol.
How many particles are in a mole?
One mole contains Avogadro's number of particles, approximately 6.022 × 10²³.