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Molarity Calculator

Molarity (M) = Mass (g) ÷ [Molar Mass (g/mol) × Volume (L)]

Example: Dissolving 58.44g of NaCl (1 mole) in 1 Liter of water yields a 1.0 M (molar) solution.

Calculate concentration parameters for chemical solutions. Solve for molarity, solute mass, molecular weight, or final solution volume.

Parameters

Result

Calculated Molarity 1.00 M

Molarity is standard temperature-dependent concentration because volume expands/contracts slightly. For temperature-independent calculations, use Molality (moles solute per kg solvent).

Understanding Molarity in Chemistry

Molarity (M) is the standard unit of concentration in analytical chemistry, biochemistry, and pharmaceutical research. A solution's molarity tells you exactly how many moles of solute (the dissolved substance) are present per liter of solution. This is critical for preparing reagents, running titrations, making buffer solutions, and ensuring reproducible experimental results.

Common lab concentrations: 1 M HCl is standard for acid-base titrations. 0.9% w/v NaCl (≈ 0.154 M) is physiological saline used in medicine. Phosphate Buffered Saline (PBS) for cell culture is typically 10 mM phosphate buffer.

Common Molar Masses Reference

NaCl (Sodium Chloride)58.44 g/mol
NaOH (Sodium Hydroxide)40.00 g/mol
HCl (Hydrochloric Acid)36.46 g/mol
H₂SO₄ (Sulfuric Acid)98.08 g/mol
Glucose (C₆H₁₂O₆)180.16 g/mol
NaHCO₃ (Baking Soda)84.01 g/mol
CaCl₂ (Calcium Chloride)110.98 g/mol

Frequently Asked Questions — Molarity

What is molarity?
Molarity (M) is the number of moles of solute dissolved in one liter of solution. It is the most common unit of concentration in chemistry. For example, a 1 M NaCl solution contains 1 mole (58.44 grams) of sodium chloride per liter of solution.
What is the molarity formula?
Molarity (M) = Moles of Solute (n) ÷ Volume of Solution (L). Since moles = mass (g) ÷ molar mass (g/mol), the full formula is: M = mass (g) ÷ [molar mass (g/mol) × volume (L)].
How do you calculate molarity from grams?
Step 1: Find the molar mass of the compound (sum of atomic masses). Step 2: Divide the mass in grams by the molar mass to get moles. Step 3: Divide moles by the volume of solution in liters. Example: 5.85g NaCl (molar mass = 58.5) in 100mL water = 0.1 moles ÷ 0.1L = 1.0 M.
What is the difference between molarity and molality?
Molarity (M) = moles solute per liter of solution. Molality (m) = moles solute per kilogram of solvent. Molarity depends on temperature (volume changes with temperature), while molality is temperature-independent. For high-precision work at varying temperatures, use molality.
How do you dilute a solution to a target molarity?
Use the dilution formula: M₁V₁ = M₂V₂. If you have a 10 M stock solution and need 500 mL of 1 M solution: V₁ = (1 M × 500 mL) ÷ 10 M = 50 mL stock solution, diluted to 500 mL total with solvent.

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