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Molarity Calculator

Calculate the molarity of a solution given mass, volume, and molecular weight.

grams
g/mol
Example: NaCl is approx 58.44 g/mol
Liters
Enter volume in Liters. (1000 mL = 1 L)
M = ⁄ MW × V
Where M = Molarity
m = Mass (g)
MW = Mol. Weight (g/mol)
V = Volume (L)
Molarity
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mol/L (M)

Enter the mass of solute, the molecular weight, and the total volume of the solution.

Understanding Molarity

Molarity is a measure of the concentration of a solute in a solution, or of any chemical species, in terms of amount of substance in a given volume. It is commonly used in chemistry to express the concentration of a chemical solution.

The Molarity Formula

The most common way to express solution concentration is molarity (M), which is defined as the amount of solute in moles divided by the volume of solution in liters:

M = moles of solute liters of solution

Since moles = mass / molecular weight, you can rearrange the formula to calculate molarity directly from mass:

M = mass (g) MW (g/mol) × Volume (L)

How to Use This Calculator

To find the molarity of your solution:

  1. Weigh the solute using a scale to find its Mass (grams).
  2. Determine the Molecular Weight (g/mol) of the solute (found on the periodic table).
  3. Measure the final volume of the solution after the solute has dissolved in Liters.
  4. Enter these values into the calculator above.