Percentage to Molarity Calculator
To use our percentage to molarity calculator, enter percentage cncentration (% w/v): of the solution (e.g., 5% means 5 grams of solute in 100 mL of solution).
Enter value of molar mass of solute, and then enter density of solution.
The calculator will compute molarity based on given inputs.
If you have a 37% w/w solution of sulfuric acid (molecular weight 98.08 g/mol) with a density of 1.84 g/mL, the calculator would process these parameters to determine the molarity, typically around 18.4 M.
When you’re working with a 12% hydrogen peroxide solution and need to calculate its molarity, the calculator would consider the solution’s density, molecular weight of H₂O₂ (34.01 g/mol), and percentage to determine that it’s approximately 3.53 M (moles/liter).
Percent to Molarity Conversion Table
| Substance | % (w/v) | Molarity (M) |
|---|---|---|
| Sodium chloride (NaCl) | 1% | 0.17 M |
| Sodium chloride (NaCl) | 5% | 0.85 M |
| Sodium chloride (NaCl) | 10% | 1.7 M |
| Glucose (C₆H₁₂O₆) | 1% | 0.055 M |
| Glucose (C₆H₁₂O₆) | 5% | 0.28 M |
| Glucose (C₆H₁₂O₆) | 10% | 0.55 M |
| Sulfuric acid (H₂SO₄) | 10% | 1.02 M |
| Sulfuric acid (H₂SO₄) | 50% | 6.88 M |
| Hydrochloric acid (HCl) | 10% | 3.05 M |
| Hydrochloric acid (HCl) | 37% | 12 M |
| Acetic acid (CH₃COOH) | 5% | 0.83 M |
| Acetic acid (CH₃COOH) | 10% | 1.67 M |
| Potassium chloride (KCl) | 1% | 0.13 M |
| Potassium chloride (KCl) | 5% | 0.67 M |
| Potassium chloride (KCl) | 10% | 1.34 M |
Percentage to Molarity Formula
Molarity (M) = (Density × Mass Percentage × 10) / (Molecular Weight of Solute)Where:
- Density is in g/mL
- Mass percentage is expressed as a whole number
- Molecular weight is in g/mol
W/W to Molarity Formula:
Molarity = (% × density × 1000) / (100 × molecular weight)W/V to Molarity Formula:
Molarity = (% × 10) / molecular weightMolality Formula:
Molality = (% × 10) / (molecular weight × kg solvent)Converting 37% hydrochloric acid (HCl) with density 1.19 g/mL:
M = (1.19 × 37 × 10) / (36.46) = 12.05 MHow to Convert Percent to Molarity?
- Identify the solution’s mass percentage
- Determine the solution’s density
- Know the molecular weight of your solute
- Apply the conversion formula
Let’s work through an example using 98% sulfuric acid (H₂SO₄):
- Density: 1.84 g/mL
- Molecular weight: 98.08 g/mol
- Percentage: 98%
M = (1.84 × 98 × 10) / 98.08 = 18.4 M
- 20% KOH solution: Density: 1.176 g/mL, M = (1.176 × 20 × 10) / 56.11 = 4.19 M
- 40% NaOH solution: Density: 1.43 g/mL, M = (1.43 × 40 × 10) / 40.00 = 14.3 M
- 15% H₂SO₄ solution: Density: 1.10 g/mL, M = (1.10 × 15 × 10) / 98.08 = 1.68 M
- 25% NH₃ solution: Density: 0.91 g/mL, M = (0.91 × 25 × 10) / 17.03 = 13.33 M
- 5% glucose solution: Density: 1.018 g/mL, M = (1.018 × 5 × 10) / 180.16 = 0.282 M
How do you convert 30% NaCl to molarity?
- Given information:
- NaCl percentage = 30%
- Density of 30% NaCl ≈ 1.197 g/mL
- Molecular weight of NaCl = 58.44 g/mol
- Applying the formula: M = (1.197 × 30 × 10) / 58.44 = 6.15 M
What is Percentage and Molarity?
Percentage concentration is a straightforward way to express how much of a dissolved substance is present in a solution. When we say a solution is 20% sodium chloride, it means 20 grams of NaCl are present in every 100 grams of solution.
Molarity (M) represents the number of moles of solute present in one liter of solution. For example, a 1M solution contains one mole of solute per liter of solution. Chemists prefer using molarity because it directly relates to the number of molecules available for reaction, making it invaluable for calculating chemical equations and preparing precise laboratory solutions.