Molarity Calculator

Calculate molarity, moles, or volume of a solution. Also compute moles from solute mass using molar mass.

Enter any two of molarity, moles, or volume to solve for the third. Or enter solute mass with molar mass to compute moles.

About this Calculator

Calculate molarity, moles, or volume of a solution. Also compute moles from solute mass using molar mass.

Formula & Calculations

Formula

M = n / V, n = M × V, V = n / M, and n = mass / molar mass

Where:

M=Molarity — moles of solute per liter of solution (mol/L)
n=Number of moles of solute
V=Volume of solution
mass=Mass of solute

Assumptions

The solution is assumed to be well-mixed and homogeneous.
Volume is the total solution volume, not just the solvent volume.
Provide any two of molarity, moles, and volume to solve for the third.

Calculation Examples

Example 1

Inputs:Moles = 0.5 mol, Volume = 1 L

Result:Molarity = 0.5 M

M = 0.5 / 1 = 0.5 mol/L.

Example 2

Inputs:Mass = 58.44 g, Molar Mass = 58.44 g/mol, Volume = 1 L

Result:Molarity = 1.0 M

n = 58.44 / 58.44 = 1 mol, then M = 1 / 1 = 1 M.

Example 3

Inputs:Molarity = 2 M, Volume = 0.25 L

Result:Moles = 0.5 mol

n = 2 × 0.25 = 0.5 mol.

Frequently Asked Questions

What does molarity measure?

Molarity (M) measures the concentration of a solution in moles of solute per liter of solution. A 1 M solution contains 1 mole of dissolved substance per liter of total solution.

How do I find moles from mass?

Divide the mass of the solute (in grams) by its molar mass (in g/mol). You can use our Molar Mass Calculator to find the molar mass of any compound.