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Mole Calculator
Convert mass to moles using molar mass.
Moles
—
Amount of substance.
| Molecules (approx) | — |
|---|---|
| Mass | — |
| Molar mass | — |
| — |
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How the Mole Calculator Works
A mole is a fixed count of particles — about 6.022 × 10²³, Avogadro’s number. To find how many moles you have, divide the mass of your sample by its molar mass (the grams per mole from the periodic table or formula). 100 grams of a substance with a molar mass of 40 g/mol is 2.5 moles.
Molar mass is the sum of the atomic masses in the formula — water (H₂O) is about 18 g/mol, table salt (NaCl) about 58.4. Multiplying moles by Avogadro’s number gives the actual number of molecules or atoms.
moles = mass ÷ molar mass
Frequently Asked Questions
How do you calculate moles?
Divide the mass of your sample (grams) by its molar mass (grams per mole). The result is the number of moles.
What is molar mass?
The mass of one mole of a substance, in grams, equal to the sum of the atomic masses in its formula. Water is about 18 g/mol.
What is Avogadro’s number?
6.022 × 10²³ — the number of particles in one mole. Multiply moles by it to get the count of molecules or atoms.
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