Skip to content
Calculator Tools
Solution & Concentration Calculators

Molality Calculator

Molality (mol of solute per kg of solvent), with the boiling and freezing point shift it causes.

Enter values

Particles each formula unit splits into: 1 for sugar, 2 for NaCl, 3 for CaCl₂

Results update as you type.

Result

Molality

1 mol/kg

Moles of solute
1 mol
Molar mass
58.44 g/mol
Boiling point rise (water)
1.024 °C
Freezing point drop (water)
3.72 °C

About the Molality Calculator

Molality (mol of solute per kg of solvent), with the boiling and freezing point shift it causes.

Also known as: molal concentration, mol/kg calculator, molality formula.

How to use this calculator

  1. Enter solute formula, mass of solute, mass of solvent, van 't hoff factor.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

b = moles of solute ÷ kg of solvent · ΔT = i·K·b

Worked example

Using the values pre-filled in the calculator above:

  • Solute formula: NaCl
  • Mass of solute = 58.44 g
  • Mass of solvent = 1 kg
  • Van 't Hoff factor = 2

the calculator returns:

  • Molality: 1 mol/kg
  • Moles of solute: 1 mol
  • Molar mass: 58.44 g/mol
  • Boiling point rise (water): 1.024 °C