🧪 M = mol ÷ L

Molarity Calculator

Calculate the molarity of any solution by entering the mass of solute, molar mass, and solution volume. Essential for chemistry, biology, and pharmaceutical labs.

MOutput
InstantResults
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g
g/mol
L
1.0000M
58.44 g ÷ (58.44 g/mol × 1 L) = 1.0000 M
Common Solutes:
🔬 Interactive Concentration Diagram

Visualize Solution Concentration

Watch how molarity changes as you adjust mass, molar mass, and volume

800 mL 600 mL 400 mL 200 mL 1.00 M 1.000 mol in 1.00 L

📐 Formula

M = mass ÷ (MM × V)

🧫 Moles of Solute

1.000 mol

📊 Concentration

1.0000 mol/L

Understanding Molarity

Molarity (M) is the most common measure of solution concentration in chemistry. It tells you how many moles of solute are dissolved per liter of solution. Molarity is fundamental for stoichiometric calculations, dilutions, and preparing standard solutions.

The Formula

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

Step-by-Step Example

Finding the molarity of a solution with 40 g of NaOH in 500 mL of solution:

  1. Mass of solute: 40 g
  2. Molar mass of NaOH: 40.00 g/mol
  3. Volume in liters: 500 mL = 0.5 L
  4. Moles = 40 ÷ 40 = 1.0 mol
  5. M = 1.0 ÷ 0.5 = 2.0 M

When Is Molarity Used?

  • Lab Preparations — Making standard solutions for titrations and experiments.
  • Dilutions — Using M₁V₁ = M₂V₂ to calculate required volumes.
  • Stoichiometry — Relating solution volumes to moles in balanced equations.
  • Pharmaceuticals — Preparing drug solutions at precise concentrations.

🔑 Key Points

  • M = moles of solute ÷ liters of solution
  • Moles = mass (g) ÷ molar mass (g/mol)
  • 1 M = 1 mol/L
  • Dilution: M₁V₁ = M₂V₂
  • Temperature can affect molarity slightly

📌 Common Molar Masses

  • NaCl — 58.44 g/mol
  • NaOH — 40.00 g/mol
  • HCl — 36.46 g/mol
  • H₂SO₄ — 98.08 g/mol
  • Glucose — 180.16 g/mol
💧 Interactive Dilution Tool

Dilution Calculator (M₁V₁ = M₂V₂)

Calculate how to dilute a stock solution to a target concentration.

M
mL
M
300.00mL
V₂ = (6 M × 50 mL) ÷ 1 M = 300.00 mL
Stock Solution
+ Solvent to dilute
50 mL stock + 250 mL solvent = 300 mL at 1.00 M
📊 Quick Reference

Common 1 M Solution Preparation

Mass of solute needed to prepare 1 liter of 1 M solution.

SoluteMolar Mass (g/mol)Mass for 1 M / 1 L
NaCl (table salt)58.44 g/mol58.44 g
NaOH (sodium hydroxide)40 g/mol40.00 g
HCl (hydrochloric acid)36.46 g/mol36.46 g
H₂SO₄ (sulfuric acid)98.08 g/mol98.08 g
Glucose (C₆H₁₂O₆)180.16 g/mol180.16 g
KMnO₄ (potassium permanganate)158.03 g/mol158.03 g
CaCl₂ (calcium chloride)110.98 g/mol110.98 g
Na₂CO₃ (sodium carbonate)105.99 g/mol105.99 g
🎛️ Interactive Explorer

Molarity vs Volume Explorer

Drag the slider to see how molarity changes when you hold mass constant and vary volume.

g
g/mol
1.00 L
1.0000 M
1.000 mol in 1.00 L
1.00 M
💧 Dilution Examples

Common Dilution Calculations

Using the dilution formula M₁V₁ = M₂V₂ to calculate required volumes.

Starting SolutionTarget MolarityFinal VolumeFormula
1.0 M HCl, 100 mL0.1 M HCl1000 mLM₁V₁ = M₂V₂ → V₂ = (1.0 × 100) / 0.1 = 1000 mL
6.0 M NaOH, 50 mL1.0 M NaOH300 mLV₂ = (6.0 × 50) / 1.0 = 300 mL
12.0 M HCl, 10 mL2.0 M HCl60 mLV₂ = (12.0 × 10) / 2.0 = 60 mL
0.5 M NaCl, 200 mL0.05 M NaCl2000 mLV₂ = (0.5 × 200) / 0.05 = 2000 mL
❓ Molarity FAQ

Frequently Asked Questions About Molarity

Common questions about molarity calculations, dilutions, and solution preparation.

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It is calculated using the formula: M = mass (g) ÷ (molar mass (g/mol) × volume (L)). For example, dissolving 58.44 g of NaCl in 1 L gives a 1.0 M solution.

Molarity (M) = moles of solute per liter of solution. Molality (m) = moles of solute per kilogram of solvent. Molality doesn't change with temperature because it's based on mass, while molarity can shift slightly since solution volume expands with heat.

The dilution equation states that the product of initial molarity (M₁) and volume (V₁) equals the product of final molarity (M₂) and volume (V₂). To dilute 50 mL of 6 M HCl to 1 M: V₂ = (6 × 50) / 1 = 300 mL. Add solvent until total volume reaches 300 mL.

To make 1 liter of a 1 M solution, weigh out exactly one molar mass of the solute in grams. For NaCl (58.44 g/mol), you need 58.44 g. For NaOH (40.00 g/mol), you need 40.00 g. Dissolve the solute and add solvent to reach exactly 1 L total volume.

Normality (N) = Molarity (M) × n-factor, where n-factor is the number of reactive equivalents per molecule. For monoprotic acids like HCl (n=1), N = M. For diprotic acids like H₂SO₄ (n=2), N = 2M. Use our normality calculator for these conversions.

Yes, molarity is temperature-dependent because it's defined per liter of solution, and liquid volume expands or contracts with temperature. At higher temperatures, the same amount of solute occupies a larger volume, slightly lowering molarity. For precise work, molality (moles per kg of solvent) is used instead since mass doesn't change with temperature.

Yes! Multiply molarity by molar mass: g/L = M × Molar Mass (g/mol). A 0.5 M NaCl solution has 0.5 × 58.44 = 29.22 g/L of NaCl dissolved. This conversion is useful for preparing solutions from known concentrations.

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Molarity Calculator

Calculate solution molarity from mass, molar mass, and volume.

Example: 58.44 g NaCl in 1 L → 1.0 M
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