Molarity Calculator
Enter any two of concentration, moles and volume, or give a mass and a formula. You get the third and the grams to weigh out.
Fill in any two of concentration, moles and volume, or give the mass and the formula (or molar mass) instead of the moles.
Worked examples
Salt solution
5.85 g NaCl made up to 500 mL
0.2002 mol/L
5.85 / 58.44 = 0.1001 mol, divided by 0.5 L.
Particles
0.25 mol/L in 2 L
0.5 mol, 3.01 x 10 to the 23 particles
0.5 x 6.022e23.
About Molarity Calculator
Molarity is the number of moles of solute dissolved in each litre of solution. It is the standard way to state the strength of a solution in chemistry, and it is written with a capital M. A one molar solution has one mole per litre. The molarity equals the moles divided by the volume in litres, so any one of the three can be found from the other two. This calculator also handles masses, so you can go straight from grams to molarity.
Give a mass of solute with its formula or molar mass, and the page converts to moles first. For example, 5.85 grams of sodium chloride made up to 500 millilitres gives about 0.2 molar. The volume means the volume of the finished solution, not the volume of solvent added. The page also gives grams per litre, the mass of solute to weigh out, and the number of particles, which is the amount in moles times the Avogadro constant.
How to use Molarity Calculator
- Enter any two of concentration, moles and volume, or give a mass of solute instead of moles.
- For a mass, type the formula or the molar mass in grams per mole.
- Choose units such as millilitres or millimoles per litre.
- Read the missing value, the grams to weigh out and the number of particles.
Common uses
- Preparing a solution of a known strength in the lab
- Working out how many moles are in a volume of solution
- Converting grams per litre to moles per litre
- Chemistry homework on concentration
Frequently asked questions
What is the molarity formula?
Molarity = moles of solute / litres of solution. A solution with 0.5 moles in 2 litres is 0.25 molar.
How do I get moles from grams?
Divide the mass by the molar mass. The page does this if you enter a mass with a formula or molar mass.
Is volume the solvent or the whole solution?
It is the whole solution. Dissolve the solid in a little solvent, then make up to the final volume in a volumetric flask.
How many particles are in a mole?
6.02214076 times ten to the twenty-third, called the Avogadro constant. The page multiplies your moles by it.