Multiply moles by the Avogadro constant
One mole is defined as exactly 6.02214076 × 1023 particles, so converting is a single multiplication. To go the other way, divide the particle count by the same constant. The rounded value 6.022 × 1023 is fine for almost all work.
Common amounts
| Moles | Particles |
|---|---|
| 0.001 mol | 6.022 × 1020 |
| 0.1 mol | 6.022 × 1022 |
| 0.5 mol | 3.011 × 1023 |
| 1 mol | 6.022 × 1023 |
| 2 mol | 1.204 × 1024 |
| 2.5 mol | 1.506 × 1024 |
| 10 mol | 6.022 × 1024 |
These counts are the number of whatever particle you specify. For a diatomic gas, multiply again by the atoms per molecule to get atoms.
Count molecules first, then atoms
- Molecules vs atoms. 1 mol of H₂O is 6.022 × 1023 water molecules, but 3 × that many atoms (2 H + 1 O), or 1.807 × 1024.
- Formula units. For ionic solids like NaCl, one mole is 6.022 × 1023 formula units, each of which splits into one Na+ and one Cl−.
- Moles are a count, not a mass. One mole of gold and one mole of hydrogen hold the same number of particles but weigh very differently, because moles measure how many, not how heavy.
Common questions
How many particles are in one mole?
Exactly 6.02214076 x 10^23. Since 2019 this is the fixed, defined value of the Avogadro constant, not a measured approximation. One mole of anything contains that many particles, whether they are atoms, molecules or ions.
What is the difference between molecules and atoms here?
The calculator gives you the number of the particle you named. One mole of oxygen gas is 6.022 x 10^23 O2 molecules, but because each molecule holds two atoms, that is 1.204 x 10^24 oxygen atoms. Decide whether you want molecules, formula units or atoms before you multiply.
Does the same formula work for ions?
Yes. Multiplying moles by the Avogadro constant works for atoms, molecules, ions or electrons alike. One mole of sodium ions is 6.022 x 10^23 Na+ ions.
Can I have a fractional number of particles?
Not in reality, since particles are whole objects. The result is a theoretical count that only makes sense for the very large populations chemistry deals with, so a decimal answer is normal and fine.
