Molarity Calculator

Concentration in mol/L from moles and volume — or solve for either one.

Molarity Calculator

Worked example result

Molarity	0.50000 mol/L
Amount of solute	1.00000 mol
Solution volume	2.00000 L

Dissolving 1 mol of solute and making the solution up to 2 L gives a 0.5 mol/L (0.5 M) solution.

Molarity is the standard concentration unit in chemistry: moles of solute per litre of solution. It links the amount of substance to the volume you measure out.

Choose a mode to solve for molarity, moles or volume. The quantity being solved for is ignored, so leave it at 0 if you like.

The formula

M = n ÷ V; n = M × V; V = n ÷ M

Worked example

Dissolving 1 mol of solute and making the solution up to 2 L gives a 0.5 mol/L (0.5 M) solution.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

Is volume the solvent or the solution?

The final solution volume — solute plus solvent after mixing. In the lab you dissolve the solute and then add solvent up to the mark on a volumetric flask.

How do I get moles from a mass in grams?

Divide the mass by the substance's molar mass (g/mol) from the periodic table. For example, 58.44 g of NaCl is 1 mol, since NaCl's molar mass is 58.44 g/mol.

Category: Science calculators

Molarity Calculator