Molarity Calculator
Calculate the molarity of a solution — its concentration in moles of solute per liter of solution. Enter the moles of solute directly, or enter the mass and molar mass and let the calculator work out the moles, then divide by the solution volume.
Calculate
Formula (optional)
Formula weight
g/mol
Mass of solute
Solution volume
What Is Molarity?
Molarity (M) is the number of moles of solute dissolved in one liter of solution. It is the most common way to express concentration in chemistry.
Note that molarity uses the total volume of the solution, not the volume of solvent added — this distinguishes it from molality.
Formula
M = moles of solute ÷ liters of solution
Example: Molarity of 0.5 mol NaCl in 2 L of solution:
0.5 ÷ 2 = 0.25 mol/L