Grams to Moles Calculator
Convert between mass and amount of substance, and find how many particles you have.
How to use the Grams to Moles Calculator
- Choose the convert.
- Choose the substance.
- Enter the molar mass.
- Enter the mass and pick its unit.
- Enter the amount.
- Press Calculate. The result updates automatically as you type, and you can switch the result unit at any time.
About the Grams to Moles Calculator
Chemical equations count particles, but balances measure mass. The mole connects the two: one mole of any substance contains Avogadro's number of particles (6.02214076 × 10²³), and its mass in grams equals the substance's molar mass. Converting grams to moles is usually the first step in any stoichiometry problem, such as finding how much product a reaction can make.
Choose a common compound from the list or select "Other" and enter the molar mass of your substance; the molar mass calculator can work it out from a formula. For ionic compounds the "particles" are formula units rather than molecules, and for elements they are atoms.
Formula
moles = mass (g) ÷ molar mass (g/mol)
mass (g) = moles × molar mass
particles = moles × 6.022 × 10²³
Example: 36 g of water ÷ 18.015 g/mol = 1.998 mol, which is about 1.203 × 10²⁴ molecules.
Example calculation
Using the default values:
- Convert = Grams → moles
- Substance = Water, H₂O (18.015)
- Mass = 36 g
the calculator returns:
- Moles: 1.99833 mol
- Number of particles: 1.203 × 10^24
- Molar mass used: 18.015 g/mol
Frequently asked questions
How do I convert grams to moles?
Divide the mass in grams by the molar mass. 10 g of NaCl ÷ 58.44 g/mol = 0.171 mol.
How do I convert moles to grams?
Multiply moles by molar mass. 2 mol of CO₂ × 44.009 g/mol = 88.02 g.
What is Avogadro's number?
It is exactly 6.02214076 × 10²³ per mole, the number of particles in one mole of any substance.
Last updated: · Category: Science calculators