basic

Mass Fraction to Molality Conversion Calculator

m = w / (M · (1 − w)) (w = mass fraction of solute).

Convert the mass fraction of a solute w (g solute / g solution) to molality b = w / (M_solute × (1 − w)), with M in kg/mol. Molality is independent of temperature and pressure, making it preferred in precise thermodynamic work.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

g/mol

Results

Enter values and click Calculate to see results.
Was this helpful?

How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

b = w / (M · (1 − w)); w = mass fraction (dimensionless), M in kg/mol.

In depth

Convert the mass fraction of a solute w (g solute / g solution) to molality b = w / (M_solute × (1 − w)), with M in kg/mol. Molality is independent of temperature and pressure, making it preferred in precise thermodynamic work.