Calculate Molality
Calculate from Solute Mass
About This Tool
Molality (m) expresses concentration as moles of solute per kilogram of solvent, and unlike molarity it is independent of temperature and pressure — making it the preferred concentration unit in thermodynamic calculations. This calculator offers two input modes: direct entry of moles and solvent mass, or entry of solute mass and molar mass from which the mole count is derived automatically. Solvent mass can be entered in grams or kilograms and is converted internally. Molality is most commonly encountered in the study of colligative properties — phenomena that depend only on the number of solute particles, not their identity — including boiling point elevation, freezing point depression, and osmotic pressure. It is also used in high-precision analytical work where volume changes with temperature would introduce error into molarity-based calculations.