Normality & Molarity Calculator

The molarity calculator tool provides lab-ready directions describing how to prepare an acid or base solution of specified Molarity (M) or Normality (N) from a concentrated acid or base solution.  To prepare a solution from a solid reagent, please use the Mass Molarity Calculator. To dilute a solution of known molarity, please use the Solution Dilution Calculator.

Acid and Base Solution Preparation

  Select acid or base:

Density: g/mL 

Formula weight: g/mol 

Weight percentage: % w/w 

Desired final volume: mL 

Desired concentration:


   http://www.sigmaaldrich.com/chemistry/stockroom-reagents/learning-center/technical-library/molarity-calculator.htmlHow is the Molarity of a percentage solution calculated?
Using 70% concentrated Nitric Acid as an example: 70% Nitric Acid means that 100 grams of this acid contains 70 grams of HNO₃. The concentration is expressed at 70% wt./wt. or 70 wt. % HNO₃. Some chemists and analysts prefer to work in acid concentration units of Molarity (moles/liter). To calculate the Molarity of a 70 wt. % Nitric Acid the number of moles of HNO₃ present in 1 liter of acid needs to be calculated. Knowing the density of the acid to be 1.413 g/mL, we can calculate the weight of 1 L of 70% HNO₃ to be 1413 grams. Knowing that the solution is 70 wt % would then allow the number of grams of HNO₃ to be calculated: (0.700)(1413g) = 989.1 grams HNO₃ per liter. Dividing the grams of HNO₃ by the molecular weight of HNO₃ (63.01 g/mole) gives the number of moles of HNO₃ / L or Molarity, which is 15.7 M.
The Molarity Calculator Equation:
The following equation is used for calculating Molarity where the concentration is given in wt %:
           [(% x d) / MW] x 10 = Molarity 
Where: % = Weight %; d = Density (or specific gravity); MW = Molecular Weight (or Formula Weight).
The above equation can then be used to calculate the Molarity of the 70 wt % Nitric Acid:
         [(70 x 1.413) / 63.01] x 10 = 15.7 M
How do I calculate the Normality of an acid or base from its Molarity? 
There is a relationship between normality and molarity. Normality can only be calculated when we deal with reactions, because Normality is a function of equivalents. Normality refers to compounds that have multiple chemical functionalities, such as sulfuric acid, H₂SO₄. A 1 M solution of H₂SO₄ will contain only one mole of H₂SO₄ in 1 liter of solution, but if the solution is titrated with a base, it will be shown to contain two moles of acid. This is because a single molecule of H₂SO₄ contains two acidic protons (H+ Ions). Thus, a 1 M solution of H₂SO₄ will be 2 N. The 'Normality' of a solution is the 'Molarity' multiplied by the number of equivalents per mole.
Why does the calculator use 56.6% weight percentage instead of 28% for Ammonium Hydroxide?
28% Ammonia (NH₃) is equal to approximately 56.6% Ammonium Hydroxide.  The Sigma-Aldrich product listings (ex. Product No. 338818) actually list the % Ammonia and not the % Ammonium Hydroxide.