Molarity Calculator

Calculate molarity (M) — moles of solute per liter of solution. The most common concentration unit in chemistry.

🧪 MOLES OF SOLUTE

mol

💧 VOLUME OF SOLUTION

MOLARITY

1 M (mol/L)

IN mM

1,000 mM

FORMULA

M = n / V

💡 How to Calculate Molarity

What Is Molarity?

Molarity is the most widely used concentration unit in chemistry. It expresses the number of moles of a solute dissolved in one liter of total solution. Molarity is represented by M and its units are moles per liter (mol/L).

A "1 M NaCl solution" means 1 mole of NaCl (58.44 g) has been dissolved in enough water to make exactly 1 liter of total solution. You can find the molar mass of any substance to determine how many grams correspond to 1 mole.

How to Calculate Molarity

Molarity Formula

M = n / V

Where:

M = molarity (mol/L)
n = moles of solute
V = volume of solution (liters)

The amount of substance in moles can be found using the molar mass and the mass of the substance: n = m / M. Use our mole calculator if you need to convert grams to moles first.

Dilution Formula

When diluting a concentrated solution, use:

M₁V₁ = M₂V₂

For example, how much 12 M HCl is needed to prepare 500 mL of 1 M HCl?

V₁ = (M₂ × V₂) / M₁ = (1 × 0.5) / 12 = 41.7 mL

Molarity vs. Molality

Molality uses mass of solvent (kg) instead of volume of solution (L). Molality is preferred for colligative properties because it is temperature-independent. For dilute aqueous solutions at room temperature, molarity and molality are approximately equal.

1 M NaCl = 58.44 g NaCl per liter of solution. Use M₁V₁ = M₂V₂ for dilution calculations.