Molarity Calculator

Calculate molarity, mass, or volume for solution preparation. Includes dilution calculator (C₁V₁=C₂V₂) and common compound molecular weights.

Results

Molarity

1 M

1000 mM

Moles1 mol
mg/mL58.44

What do you want to calculate?

Formula: M = (mass / MW) / V

Molecular Weight

Common compounds (click to select):

Enter Values

Results

Molarity

1 M

1000 mM

Mass

58.44 g

58440 mg

Volume

1000 mL

1 L

Moles

1

58.44 mg/mL

Common Compound Molecular Weights

CompoundMW (g/mol)Action
Sodium Chloride (NaCl)58.44
Glucose (C₆H₁₂O₆)180.16
Sulfuric Acid (H₂SO₄)98.079
Hydrochloric Acid (HCl)36.46
Sodium Hydroxide (NaOH)40
Acetic Acid (CH₃COOH)60.05
Ethanol (C₂H₅OH)46.07
Calcium Chloride (CaCl₂)110.98
Potassium Chloride (KCl)74.55
Magnesium Sulfate (MgSO₄)120.37
Sodium Bicarbonate (NaHCO₃)84.01
Urea (CH₄N₂O)60.06

Quick Answer

Molarity (M) = Moles of solute / Liters of solution. Example: 0.5 moles NaCl in 2 liters = 0.5/2 = 0.25 M solution. For dilutions, use C1V1 = C2V2: if you have 1M stock and need 0.1M, then 1 x V1 = 0.1 x 1000mL, so V1 = 100mL stock diluted to 1000mL total.

Key Facts

  • Molarity (M) = moles of solute / liters of solution
  • Units: mol/L or M (molar)
  • Dilution formula: C1V1 = C2V2
  • Moles = mass (g) / molecular weight (g/mol)
  • Molality (m) is different: moles per kg of solvent
  • 1 M = 1000 mM (millimolar)
  • Standard solutions: 1M, 0.1M, 0.01M common
  • For dilution: add stock to water, not water to stock

Frequently Asked Questions

Molarity (M) is a measure of concentration expressed as moles of solute per liter of solution (mol/L). A 1 M solution contains 1 mole of solute dissolved in enough solvent to make 1 liter of total solution.
Molarity = (mass in grams / molecular weight) / volume in liters. First calculate moles (mass ÷ MW), then divide by the solution volume. For example: 58.44g NaCl in 1L water = 58.44/58.44/1 = 1M.
C₁V₁ = C₂V₂ where C₁ is initial concentration, V₁ is volume of stock solution needed, C₂ is final concentration, and V₂ is final volume. This assumes the solute amount stays constant during dilution.
Molecular weight (MW) is the sum of atomic weights of all atoms in a molecule, expressed in g/mol. Find it by adding atomic weights from the periodic table. NaCl: Na(23) + Cl(35.5) = 58.5 g/mol.
Calculate the mass needed: mass = molarity × molecular weight × volume. Weigh the solute, add about 80% of final volume of solvent, dissolve completely, then add solvent to reach final volume (volumetric flask recommended).