Skip to main content

Molarity Calculator

Solve any one of moles of solute, solution volume, or molarity using M = n / V. Volume is the total solution volume. Informational, not a lab protocol or chemical safety guide.

Rated 4.8 out of 5 based on 218 reviews

Results

How to use the molarity calculator

  1. Enter exactly two of moles, solution volume, and molarity. Leave the value you want solved blank.
  2. Pick the volume unit that matches your measurement. Milliliters convert to liters before M = n / V.
  3. Read molarity in mol/L, moles of solute, and solution volume in liters.
  4. Treat the result as arithmetic for study or planning. It is not a lab protocol. Nothing is uploaded.

Molarity

Amount concentration in moles per liter of solution

SymbolM or mol/L
FormulaM = n / V
nAmount of solute in moles
VTotal solution volume in liters
SoluteThe dissolved substance counted in moles
Versus molalityMolarity uses solution volume; molality uses kilograms of solvent

What molarity measures

Molarity is the amount of solute in moles divided by the total volume of solution in liters. A 2 mol/L solution holds two moles of solute in every liter of finished solution. The default 0.5 mol in 0.25 L is 2 mol/L.

Solute, solvent, solution, and concentration

The solute is what you dissolve. The solvent is the liquid that does most of the dissolving. The solution is the mixture after mixing. Molarity counts solute moles against solution volume, so adding solvent that expands volume changes M even when moles stay fixed.

How this page solves M = n / V

Enter any two known values and leave the third blank. The page converts milliliters, microliters, or cubic meters to liters, then solves the missing term. Filling all three fields or leaving two blank produces an error so the solve step stays determined.

Limits

The model ignores activity, temperature expansion, and purity. Informational only. Not a lab protocol, SDS substitute, or chemical safety guide. CZNull does not receive the numbers. See the disclaimer.

Molarity questions

Is molarity the same as molality?
No. Molarity divides moles by liters of solution. Molality divides moles by kilograms of solvent.
Can I enter volume in milliliters?
Yes. Choose milliliters in the volume unit list. The page converts to liters before it applies M = n / V.
Why must I leave one field blank?
The page solves exactly one unknown. Two known values fix the third. Filling all three or leaving two blank is underdetermined or overdetermined.
Does this page upload my concentrations?
No. The arithmetic runs in the page you opened. CZNull does not receive moles or volumes.
Does molarity use solvent volume or solution volume?
Solution volume. After the solute dissolves, use the final filled volume of the mixture, not the solvent volume you started with.