Molarity Calculator

Calculate molarity, moles, or solution volume using M = mol/L. Enter the solute mass to automatically compute moles. Includes common compound reference table for chemistry students.

Molarity: The Standard Concentration Unit

Molarity (M) is the number of moles of solute per liter of solution. It is the standard unit of concentration in chemistry and is essential for stoichiometry, titration calculations, and preparing solutions. To prepare a 0.5 M NaCl solution, dissolve 0.5 moles (29.22 g) of NaCl in enough water to make 1 liter of solution.

Common Compounds

CompoundMolar Mass (g/mol)
NaCl (Table Salt)58.44 g/mol
HCl (Hydrochloric Acid)36.46 g/mol
H₂SO₄ (Sulfuric Acid)98.08 g/mol
NaOH (Sodium Hydroxide)40 g/mol
C₂H₅OH (Ethanol)46.07 g/mol
CaCO₃ (Calcium Carbonate)100.09 g/mol
CO₂ (Carbon Dioxide)44.01 g/mol
NH₃ (Ammonia)17.03 g/mol
KMnO₄ (Potassium Permanganate)158.03 g/mol
C₆H₁₂O₆ (Glucose)180.16 g/mol

Frequently Asked Questions

What is molarity?
Molarity (M) is the number of moles of solute per liter of solution. It is the most common way to express concentration in chemistry. The formula is M = mol/L. For example, dissolving 1 mole of NaCl (58.44 g) in enough water to make 1 liter of solution produces a 1 M (1 molar) NaCl solution. Molarity changes with temperature because volume expands when heated.
How do I calculate molarity from mass?
First, convert the mass of solute to moles using the molar mass: moles = mass ÷ molar mass. Then divide by the volume in liters: M = moles ÷ L. For example, dissolving 29.22 g of NaCl (molar mass 58.44 g/mol) in 0.5 L of water gives (29.22 ÷ 58.44) ÷ 0.5 = 1.0 M solution.
What is the difference between molarity and molality?
Molarity (M) is moles of solute per liter of solution, which depends on volume and changes with temperature. Molality (m) is moles of solute per kilogram of solvent, which depends on mass and does not change with temperature. Molality is preferred for experiments involving temperature changes, like boiling point elevation and freezing point depression.

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