Avogadro's Number Calculator — Moles ↔ Particles
Enter moles (or particles, or mass + molar mass) to convert between amount of substance, number of particles and mass using Avogadro's constant — the bridge between the macroscopic and atomic scales of chemistry.
Calculate from
mol
g/mol
9.0332e+23 atoms / molecules / formula units
- 1
Avogadro's constant
Nₐ = 6.02214076 × 10²³ mol⁻¹Exact value fixed by the 2019 SI redefinition. - 2
Number of particles
1.5 mol × 6.02214076 × 10²³ = 9.033e+23
How does this calculator work?
N = n × Nₐ, where Nₐ = 6.02214076 × 10²³ mol⁻¹. Given moles, multiply by Nₐ to get number of particles; given particles, divide by Nₐ. If molar mass (g/mol) is provided, convert mass to moles first (n = m ÷ M). One mole of any substance contains the same number of particles.
Formula
How this is calculated
Avogadro's constant (Nₐ = 6.02214076 × 10²³ mol⁻¹) defines how many elementary entities — atoms, molecules, ions or formula units — are contained in exactly one mole of a substance. It was fixed at this exact value by the 2019 revision of the SI system. The mole is the SI base unit for amount of substance, chosen so that one mole of any element has a mass in grams equal to its relative atomic mass (e.g., 12 g for carbon-12).
The calculator supports three conversion directions. Given moles, it multiplies by Nₐ to give the number of particles; optionally, if you provide the molar mass, it also computes the mass in grams (m = n × M). Given a number of particles, it divides by Nₐ to give moles. Given mass and molar mass, it first computes moles (n = m ÷ M) and then multiplies by Nₐ for particle count.
Note that the number of particles is astronomically large for even tiny amounts of substance — one mole of water contains roughly 6 × 10²³ molecules. The visualisation scales logarithmically so the dots remain meaningful on screen.
Frequently asked questions
Avogadro's constant (6.02214076 × 10²³ mol⁻¹) was chosen so that one mole of carbon-12 atoms weighs exactly 12 grams — making atomic masses directly readable in grams per mole. The 2019 SI revision fixed the constant at its current exact value by definition.
Add the relative atomic masses of all atoms in the molecular formula (available on any periodic table). For example, H₂O: 2×1.008 + 15.999 = 18.015 g/mol. For NaCl: 22.990 + 35.453 = 58.443 g/mol. The molar mass lets you convert between grams and moles.
Atoms and molecules are vanishingly small — a single water molecule has a mass of about 2.99 × 10⁻²³ g. To weigh a practically useful amount (18 g of water ≈ 18 mL) you need ~6 × 10²³ of them. Avogadro's number bridges the atomic (nanogram) scale and the laboratory (gram) scale.
Also known as
TG we-Calculate Editorial Team. (2026). Avogadro's Number Calculator — Moles ↔ Particles [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/avogadro-calculator
TG we-Calculate Editorial Team. "Avogadro's Number Calculator — Moles ↔ Particles." TG we-Calculate. 2026. https://we-calculate.com/calculator/avogadro-calculator.
TG we-Calculate Editorial Team, "Avogadro's Number Calculator — Moles ↔ Particles," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/avogadro-calculator
@misc{wecalculate_avogadro_calculator, title = {Avogadro's Number Calculator — Moles ↔ Particles}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/avogadro-calculator}}, year = {2026}, note = {TG we-Calculate} }
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