Molarity Calculator

Molarity is the concentration of a solution measured in moles of solute per litre of solution, written mol/L or M. A 1 M solution holds one mole of dissolved substance in every litre.

Molarity equals moles of solute divided by volume of solution in litres, M = n / V. Rearranged, n = M times V and V = n / M, and the calculator uses whichever form solves for your chosen unknown.

Divide the mass in grams by the molar mass in grams per mole. Select the Mass plus molar mass option and the tool computes n = mass / molarMass automatically before finding the concentration.

Use the total volume of the finished solution, not the volume of solvent you started with, because the dissolved solute also takes up space. This matters most for concentrated solutions.

Divide millilitres by 1000, so 250 mL becomes 0.25 L. The volume field expects litres, so convert first and then type the litre value.

Moles are found by dividing mass by molar mass, so a molar mass of zero would be a division by zero. If you leave it at zero the tool reports that molar mass must be greater than zero.

The engine needs exactly two of moles, volume and molarity, counting a mass plus molar mass pair as the moles. If you supply too few or too many it asks you to provide exactly two so the equation stays solvable.

No. Molarity is moles per litre of solution and changes slightly with temperature as volume expands, while molality is moles per kilogram of solvent and does not. Use a molality calculator when temperature stability matters.

No. All the arithmetic runs locally in your browser, so your masses, volumes and concentrations stay on your own device.