Moles to grams converter (and back)
Convert between moles and grams using the molar mass, and see the number of particles.
Molar mass links mass (g) and amount of substance (mol): mol = mass ÷ molar mass. 1 mol has 6.022 × 10²³ particles (Avogadro's number).
How the calculation works
The amount of substance is moles = mass (g) ÷ molar mass (g/mol), and mass is the reverse: mass = moles × molar mass. To find a compound's molar mass, use the molar mass calculator.
Examples
- 36 g of water (18 g/mol): 36 ÷ 18 = 2 moles.
- 0.5 mol of NaCl (58.5 g/mol): 0.5 × 58.5 = 29.25 g.
Frequently asked questions
What is 1 mole?
It is a fixed count of particles: 6.022 × 10²³. Just as a dozen is 12, a mole is 6.022 × 10²³ atoms or molecules.
How do I find the compound's molar mass?
Add the atomic masses of each element in the formula. Use the molar mass calculator.
Why convert between moles and grams?
Reactions happen in mole ratios, but we weigh in grams. The conversion links the two (stoichiometry).
How do I convert grams to moles?
Divide mass by molar mass. 25 g of NaCl (58.44 g/mol) is 0.4278 mol. To reverse it, multiply.
Why not apply the ratio directly to masses?
Because a chemical equation gives the ratio between particle counts, not masses. Converting to moles is the required bridge.
What volume does one mole of gas occupy?
At STP (0 °C, 1 atm), 22.4 litres for any gas. Outside those conditions, use PV = nRT.
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See all →Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources