Molality Calculator
Calculate molality from moles of solute and mass of solvent, or solve for moles or solvent mass given the other two values.
Solve For
Mass of solvent only — do not include solute mass.
Formula Reference
m = n / kgsolvent
- m = molality (mol/kg)
- n = moles of solute (mol)
- kgsolvent = mass of solvent (kg)
Result
Enter values on the left to calculate.
All three values will be shown once computed.
Molality
—
mol/kg
| Variable | Symbol | Value | Unit |
|---|---|---|---|
| Molality | m | — | mol/kg |
| Moles of Solute | n | — | mol |
| Solvent Mass | kgsolvent | — | kg |
| Also in grams | — | g |
Working
Summary
Calculate molality from moles of solute and mass of solvent, or solve for moles or solvent mass given the other two values.
How it works
- Select which variable you want to solve for: Molality, Moles of Solute, or Solvent Mass.
- Enter the two known values in the appropriate fields.
- The calculator applies the formula m = n / kg_solvent and displays the result.
- Switch the solvent mass unit between kilograms and grams as needed.
- Results update live — no button press required.
Use cases
- Chemistry students solving colligative property problems (boiling-point elevation, freezing-point depression).
- Lab technicians preparing solutions where temperature stability of concentration is required.
- Calculating how many moles of solute are needed to reach a target molality.
- Finding how much solvent is required to dissolve a known amount of solute at a given molality.
- Electrochemistry work requiring concentration expressed independently of temperature.
- Cross-checking textbook exercises on solution stoichiometry.
Frequently Asked Questions
Last updated: 2026-06-09 ·
Reviewed by Nham Vu