Molarity Calculator

Molarity (M) = moles of solute ÷ liters of solution. First convert mass to moles by dividing by the molar mass (moles = grams ÷ g/mol), then divide by the volume in liters. This calculator does both steps.

Divide the mass in grams by the molar mass to get moles, then divide moles by the solution volume in liters. For example, 58.44 g of NaCl (molar mass 58.44 g/mol) in 1 L is 1 mole ÷ 1 L = 1 M.

Molar mass is the mass of one mole of a substance, in grams per mole (g/mol), found by adding the atomic masses of all atoms in the formula. Water (H₂O) is about 18.02 g/mol; sodium chloride (NaCl) is 58.44 g/mol.

Molarity uses the volume of the whole solution (mol per liter). Molality uses the mass of the solvent (mol per kilogram) and does not change with temperature. This tool calculates molarity.

Rearrange the formula: grams needed = molarity × volume (L) × molar mass. To make 0.5 L of 2 M NaCl: 2 × 0.5 × 58.44 = 58.44 g dissolved and topped up to 0.5 L.