About this calculator
Avogadro’s number is 6.02214076 × 10²³ per mole, exact since 2019.
How to use it
- Enter the formula or molar mass.
- Choose what you know and enter it.
- Read moles, mass, particles and volume.
The formula
n = mass ÷ molar mass = particles ÷ Nₐ = gas volume ÷ 22.4 L
- n
- amount in moles
- Nₐ
- Avogadro constant
Worked example
36 g of water
- Molar mass of H2O = 18.015 g/mol.
- n = 36 ÷ 18.015 = 2.00 mol, or 1.20 × 10²⁴ molecules.
What the result means
One mole of any gas fills about 22.4 L at 0 °C and 1 atm.
Assumptions
- Ideal gas behaviour for the volume.
Limitations
- Gas volume applies only to gases.
Frequently asked questions
How do I convert grams to moles?
Divide the mass by the molar mass.
What is Avogadro’s number?
6.022 × 10²³, the number of particles in one mole.
Why does NCERT use 22.7 L?
At 0 °C and 1 bar a mole of gas fills 22.7 L; at 1 atm it is 22.4 L.
Last reviewed on 6 October 2026. Found a mistake? Tell us.