Calculate Molality from Moles and Mass of Solvent

Instantly determine the molality of a solution using moles of solute and mass of solvent. Supports mol, mmol, kg, and g units. Ideal for chemistry students, lab technicians, and researchers.

Whether you’re preparing solutions in a laboratory, studying for exams, or performing chemical calculations, our free online molality calculator ensures quick, accurate, and unit-flexible results.

Calculate Your Molality
1.000 m
Dilute
Moles (mol)
1.000
Mass (kg)
1.000
Molality Formula
m = n / mass of solvent (kg)

Where:

  • m = molality (mol/kg)
  • n = moles of solute (mol)
  • mass of solvent = mass in kilograms (kg)

Example: 2.5 mol of NaCl dissolved in 1.5 kg of water gives molality = 2.5 ÷ 1.5 = 1.67 m

What is Molality?

Molality (m) is a concentration unit that expresses the number of moles of solute per kilogram of solvent. Unlike molarity, molality is temperature-independent because it's based on mass rather than volume, making it ideal for studying colligative properties and temperature-dependent processes.

Units

Molality is expressed in mol/kg or simply "m" (molal).

Notes

Temperature independent, used for colligative properties.

Related

Molarity, Normality, Dilution calculators.

Where is Molality Used?
  • Chemical laboratories for precise concentration measurements
  • Colligative property studies (freezing point depression, boiling point elevation)
  • Freezing and boiling point change calculations
  • Pharmaceutical formulations and drug preparations
  • Industrial chemistry processes requiring temperature stability
  • Research involving temperature-dependent reactions
Frequently Asked Questions