Molarity calculator
Enter the solute formula, its mass and the final solution volume to get the molar concentration. Useful for chemistry students and lab technicians.
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How to use it
- Enter solute formula, solute mass, final solution volume and volume unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Molarity C (mol/L) = (mass ÷ molar mass) ÷ solution volume in liters.
Example
Inputs: Solute formula = NaCl, Solute mass = 5.844 g, Final solution volume = 100, Volume unit = milliliters (mL). Result: Molarity: 1.000004 mol/L; Moles of solute: 0.1 mol; Concentration in mmol/L: 1,000.0039 mmol/L.
Limits and caveats
- Use the final solution volume after dissolving, not the volume of water added.
- Ignores the effect of temperature on volume and does not account for dissociation into ions.
Questions about this tool
What is the difference between molarity and molality?
Molarity is moles of solute per liter of solution; molality is moles of solute per kilogram of solvent.
What is the molarity of 5.844 g NaCl in 100 mL?
That is about 0.1 mol in 0.1 L, so roughly 1 mol/L.
Is M the same as mol/L?
Yes. A 0.5 M solution contains 0.5 mol of solute in every liter.