🔢 Mole Calculator (Grams ↔ Moles ↔ Particles)
Convert grams ↔ moles ↔ particles for any substance, type a formula to auto-fill the molar mass, and read all three at once.
Moles
1 mol
Mass
18.015 g
Particles
6.0221e+23
moles = mass ÷ molar mass; particles = moles × Avogadro (6.022×10²³). 🔒 Computed in your browser.
How the mole calculator (grams ↔ moles ↔ particles) works
Moles = mass ÷ molar mass; particles = moles × Avogadro’s number (6.02214076×10²³). Enter a chemical formula and the molar mass is computed from atomic weights; give any one of mass, moles or particles and the tool returns the other two. So mass = moles × molar mass, and moles = particles ÷ Avogadro’s number, letting you move freely between all three, one mole of carbon-12 is 12 g and contains 6.022×10²³ atoms.
The everyday conversion at the heart of stoichiometry. Type NaCl and it fills 58.44 g/mol; enter grams and read moles and the particle count instantly.
Frequently asked questions
How do I convert grams to moles?
Divide the mass in grams by the molar mass (g/mol). 18.015 g of water ÷ 18.015 g/mol = 1 mole. Enter a formula and the tool supplies the molar mass, then converts.
How do I convert moles to particles?
Multiply the number of moles by Avogadro’s number, 6.022×10²³. One mole of any substance contains that many molecules (or atoms/ions).
What is Avogadro’s number?
The number of particles in one mole: 6.02214076×10²³ (its exact defined value). It links the mole to a count of atoms or molecules.
Can it use a molar mass I already know?
Yes. You can type the molar mass directly instead of a formula, and the conversions use that value.
Is my calculation private?
Yes, everything runs in your browser.
How many molecules are in 18 g of water?
That is one mole (18.015 g/mol), so 6.022×10²³ molecules. Halve the mass to 9 g and you have half a mole, 3.011×10²³ molecules.
How do I convert particles back to grams?
Divide the particle count by Avogadro’s number to get moles, then multiply by the molar mass. 1.2×10²⁴ molecules of water ÷ 6.022×10²³ = 1.99 mol × 18.015 ≈ 35.9 g.