Molality calculator
Compute molality (mol/kg) from moles of solute and kilograms of solvent.
Calculator
How to use
Molality
Molality uses kilograms of solvent (not solution volume):
$$m = \frac{n}{m_{\text{solvent}}}$$
- Independent of temperature-driven volume change—useful for colligative reasoning.
- Distinct from molarity when density is not 1 kg/L.
When to use
- Boiling-point elevation / freezing-point depression estimates.
- Problems that specify solvent mass instead of flask volume.
Educational use only. Double-check values for labs, homework, and exams.