Moles Calculator

Moles Formula

Worked Example

36.03 g of water (M = 18.015 g/mol):

1. n = m ÷ M
2. n = 36.03 ÷ 18.015
3. n = 2 mol

In µmol: 2000000 µmol · Number of particles n × Nₐ: 1.204428152 × 10²⁴ · Avogadro constant Nₐ (exact): 6.02214076 × 10²³ mol⁻¹

Stoichiometry in three steps

Grams of A → moles of A (÷ M), moles of A → moles of B (× ratio from the balanced equation), moles of B → grams of B (× M). This calculator handles the first and last steps.

More Moles and Concentration Calculators

• Molar Mass Calculator

  M = Σ nᵢ Aᵢ

  nᵢ number of atoms of each element, Aᵢ its standard atomic weight (g/mol)

  Example: Sulfuric acid, H2SO4: Molar mass M = 98.072 g/mol.

  Open the molar mass calculator →

• Molarity Calculator

  c = m / (M × V)

  c molarity (mol/L), m mass of solute (g), M molar mass (g/mol), V volume of solution (L)

  Example: 29.22 g of sodium chloride (M = 58.44 g/mol) made up to 1 litre: Molarity c = 0.5 mol/L (M).

  Open the molarity calculator →

• Dilution Calculator

  C₁ V₁ = C₂ V₂

  C₁ stock concentration, V₁ stock volume, C₂ final concentration, V₂ final volume

  Example: Making 1 L of 0.1 M solution from a 2 M stock: Stock volume needed V₁ = 0.05 L.

  Open the dilution calculator →

Frequently asked questions

Sources

• CODATA Recommended Values of the Fundamental Physical Constants: 2018, National Institute of Standards and Technology .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.