Moles to Atoms Calculator — Avogadro's Number Converter
Convert any amount in moles to the equivalent count of atoms or molecules using Avogadro's constant (6.022 × 10²³ /mol). Optionally enter the molar mass to also get the sample mass in grams.
mol
g/mol
- 1
Amount of substance n
1 mol - 2
Atoms N = n × Nₐ
1 mol × 6.022 × 10²³ /mol = 6.022 × 10^23Avogadro's constant Nₐ = 6.02214076 × 10²³ mol⁻¹ (exact, 2019 SI).
How does this calculator work?
Multiply moles by Avogadro's constant to count atoms: N = n × 6.022 × 10²³. For 0.5 mol you get 3.011 × 10²³ atoms. Enter a molar mass to also get grams: m = n × M. Avogadro's constant is fixed at exactly 6.02214076 × 10²³ mol⁻¹ by the 2019 SI system.
Formula
How this is calculated
A mole is the SI base unit for amount of substance, equal to exactly 6.02214076 × 10²³ elementary entities — atoms, molecules, ions, or any other specified particle. This number is Avogadro's constant Nₐ, fixed at this precise value by the 2019 SI redefinition. To convert moles to atom count, multiply: N = n × Nₐ. For 2 mol of water that gives 2 × 6.022 × 10²³ ≈ 1.204 × 10²⁴ molecules.
If you know the molar mass M of the substance (in g/mol — the same number as the molecular weight), you can also convert to grams: m = n × M. Enter the molar mass directly, or use the Molecular Weight Calculator to derive it from the chemical formula. For water M = 18.015 g/mol, so 2 mol weighs 36.03 g.
Note on 'atoms' vs 'molecules': this calculator counts formula units. For H₂O, 1 mol gives 6.022 × 10²³ molecules but 3 × 6.022 × 10²³ individual atoms (2 H + 1 O per molecule). The result shown here is the number of formula units — molecules for covalent compounds, formula units for ionic compounds like NaCl.
Frequently asked questions
Avogadro's constant is exactly 6.02214076 × 10²³ per mole (mol⁻¹). It represents the number of elementary entities in one mole of any substance. Since 2019 it is a defined constant in the SI system, no longer a measured value.
Divide the number of atoms by Avogadro's constant: n = N / Nₐ. For 1.204 × 10²⁴ atoms that gives 1.204 × 10²⁴ ÷ 6.022 × 10²³ = 2 mol.
The molar mass (g/mol) is the mass of one mole and varies per substance. 1 mol of H₂O (M = 18.015 g/mol) weighs 18.015 g; 1 mol of NaCl (M = 58.44 g/mol) weighs 58.44 g. Without knowing the substance you cannot convert moles to grams.
Also known as
TG we-Calculate Editorial Team. (2026). Moles to Atoms Calculator — Avogadro's Number Converter [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/moles-to-atoms-calculator
TG we-Calculate Editorial Team. "Moles to Atoms Calculator — Avogadro's Number Converter." TG we-Calculate. 2026. https://we-calculate.com/calculator/moles-to-atoms-calculator.
TG we-Calculate Editorial Team, "Moles to Atoms Calculator — Avogadro's Number Converter," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/moles-to-atoms-calculator
@misc{wecalculate_moles_to_atoms_calculator, title = {Moles to Atoms Calculator — Avogadro's Number Converter}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/moles-to-atoms-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?